Easy Sauteed Kale and Onions with Balsamic Reduction

Today’s recipe for sauteed kale and onions with balsamic reduction is one of my family’s favorite vegan side dishes that’s easy to make for a weeknight dinner, yet fancy enough for special occasions like Thanksgiving or St. Patrick’s Day. Tender, juicy cooked kale is full of bright, garlicky flavor with just a touch of sweetness from balsamic vinegar.

This recipe is free of common food allergens, and works well for vegan, vegetarian, keto, or gluten-free diets.

Meatless sauteed kale and onions in balsamic sauce - a healthy vegetarian side dish made with simple ingredients

(Note: don’t be afraid of “balsamic reduction” in this recipe’s name – it sounds fancy but actually it’s very easy! All you’ll need is a splash of your favorite balsamic vinegar, however fancy or cheap.)

While I could eat leafy greens in any shape or form, my husband and daughter have often been less than thrilled when they saw sauteed kale on their plates. The tough texture or bitter flavor have been a turn-off for them.

But recently I figured out a secret to making perfectly tender sauteed kale and onions with pleasantly bright flavor that’s not bitter at all.

So today I’m sharing my method with you – you’ll be amazed at the difference this little secret step makes!

Traditionally, most vegan side dishes with kale are cooked for a while to reduce the toughness and bitterness of kale leaves. The problem with this method is that kale loses a lot of its nutrients if it’s cooked for a long time.

That’s not a big deal if preserving nutrition of kale isn’t our main goal (it’s better to eat vegetables without some of their nutrients than no vegetables at all, right?).

But if we want to reduce nutrient loss, we would need to cook kale for a shorter period of time. Only here’s a catch-22: if we reduce the cooking time, then our sauteed kale stays tough.

So what can we do to make kale in our side dishes more tender and flavorful while cooking it quickly?

Here’s what I discovered from my own experience:

WE’VE GOT TO MASSAGE THE BEJESUS OUT OF KALE LEAVES!

Okay, I know that massaging kale isn’t a new concept. Internet has been abuzz in the past few years with recipes for massaged kale salads – so much so that they’ve become an eye roll-worthy cliché.

If you’re still not a fan of fresh kale salads, massaged or not, just give it a try in my recipe for sauteed kale and onions with balsamic reduction. It actually feels kind of cathartic to give a good “beating” to a big pile of kale leaves 🙂

Let’s talk about the ingredients I use in this recipe, and what each of them does for this veggie side dish.

Sauteed balsamic kale with garlic and shallots - an easy veggie side dish recipe for any occasion

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Ingredients for Sauteed Kale and Onions in BALSAMIC Reduction

Kale leaves. Since kale is the star of this dish, we want to use fresh, brightly colored leaves of curly or lacinato (a.k.a. Italian or dinosaur) kale.

Kale is chock-full of nutrients like vitamins A, K and C, as well as calcium, potassium and phosphorus. 100 grams (3.5 ounces) of chopped raw kale provides 4.3 grams of protein at only 49 calories.

It’s well known that some vitamins in kale can break down during cooking. To keep nutrient loss to a minimum (and retain beautiful green color of its leaves), we’re going to cook kale quickly, for only 1-2 minutes.

Garlic cloves. Garlic is a well-known flavor and nutrition superstar. It’s rich in B vitamins A and C, folate, calcium, potassium, and disease-fighting flavonoids (source).

Just like in the case of kale, the longer we cook garlic, the more of its nutrients will break down. That’s why we’re only cooking it for 30 seconds before adding kale for 1-2 minutes.

Small onion (or shallot). Yet another nutrient-dense vegetable in our recipe: onions contain vitamins C, B, potassium, and antioxidants that fight inflammation. While red onion has more nutrients than white or yellow, shallots appear to be even more nutritious.

I like using shallots in this recipe because they add a more complex flavor, but either red or yellow onions will work too.

Salt and pepper. The classic seasoning combo for any occasion – need I say more?

Balsamic vinegar. This is a true game changer for sauteed leafy greens like kale or spinach. When a splash of balsamic vinegar is added to the hot pan at the end of cooking, it immediately starts to sizzle.

As the liquid evaporates, it turns the vinegar into balsamic reduction with a deeper umami flavor accented by just a touch of sweetness.

My husband actually found that kale tastes a lot like steak (a nod to our pre-vegan days) when cooked following my recipe below.

Tip: it’s important to add vinegar (or lemon juice, or any other acidic component) to cooked leafy greens at the very end of cooking. If we add it too early, the acidity will turn the green leaves brown – not bad flavor-wise, but not very appealing to look at.

Red pepper flakes (optional). Red pepper flakes add a spicy touch to my sauteed kale and onions without overpowering their flavor. If you don’t like spicy food, feel free to skip them.

Sauteed kale and onions in balsamic vinegar reduction - a healthy and easy vegan side dish recipe

How to Make Balsamic Sauteed Kale and Onions

To make balsamic sauteed kale and onions, set out and prep all ingredients first. For full ingredients list and amounts see the recipe card below.

Rinse kale leaves under warm running water. Remove and discard thick stems, and tear the leaves into bite-sized pieces.

Rub the kale pieces together, squeeze them with your hands, or massage them in any other way you like to thoroughly break them down. This takes about 2 minutes. The kale will soften, reduce in volume, and turn a darker shade of green.

Next, peel and thinly slice a small onion or a shallot. Peel and mince garlic cloves.

Other ingredients to set out: balsamic vinegar, salt, pepper, crushed pepper flakes (optional – skip if you don’t want a hint of spice in your sauteed kale), and high heat-resistant cooking oil like avocado or grapeseed (alternatively, use cooking spray).

Preheat a large heavy-bottomed skillet (I use the 12-inch skillet from this set by Anolon) or a cast iron pan over medium heat. Add a splash of oil. Saute sliced onions (or shallot) for 5-6 minutes, stirring often, until they soften and turn golden brown.

Increase the heat to medium-high. This will help the rest of the dish cook quickly while infusing the vegetables with maximum flavor.

Stir minced garlic into the onions (or shallots) and cook until it releases its aroma, about 30 seconds.

Add massaged kale leaves and mix briefly. Cover with a lid and let the kale “sweat” for about 2 minutes. It will reduce in volume and turn bright green.

Remove the lid, sprinkle the kale with salt and pepper, mix well. Take the pan off the heat and immediately add a splash of balsamic vinegar. Toss the kale as the vinegar sizzles and starts evaporating. Make sure to get some of the vinegar reduction on all pieces of kale.

Taste and adjust seasoning. Serve sprinkled with red pepper flakes if desired.

How to make balsamic sauteed kale and onions - a healthy meatless side dish for weeknight dinners or special occasions like Thanksgiving

Alternative Ways to Serve

While I like to serve my sauteed kale and onions with just a dash of red pepper flakes, this is one of those vegan side dishes that can be easily glammed up. Toss in some toasted pine nuts or pumpkin seeds, or sprinkle with nutritional yeast for a cheesy but dairy-free flavor.

If you’re serving this sauteed kale as a side dish for Thanksgiving, add a handful of dried cranberries into the pan with kale at the end of cooking.

Or you can even turn this dish into a main course: top the cooked kale with some chickpeas and serve on a bed of my easy 20-minute vegan mashed potatoes or cooked rice.

How to Store Sauteed Balsamic Kale and Onions

Sauteed kale and onions keep well when refrigerated in an air-tight container for 4-5 days. Most containers with a tight-fitting lid will work, but I like the classic glass containers by Pyrex that are also dishwasher-safe.

To reheat sauteed kale, pop it into a microwave for 30 seconds, then stir and check if it’s reheated evenly. If you find cold bits, microwave for another 10-15 seconds.

What to Serve with Sauteed Kale and Onions

This sauteed kale side dish is quite versatile for many reasons:

– It’s easy to make both for a quick weeknight meal and a special occasion dinner like Thanksgiving or Christmas.

– It makes a delicious and healthy vegan meal paired with homemade BBQ seitan, BBQ chickpeas, or served with other vegan side dishes like Southern-style Instant Pot black eyed peas or simple roasted butternut squash.

– The ingredients for this sauteed kale and onions recipe are available year round.

If you’re looking for more vegan side dishes with leafy greens, check out my easy smoky Southern-style slow cooker collard greens and smoky roasted Brussels sprouts.

If you’ve tried this recipe, I’d love to hear how it turned out! Give it a star rating below, pin it to Pinterest, tag @vegan_runner_eats on Instagram, or leave a comment.

Yield: 2 servings

Balsamic Sauteed Kale and Onions

Closeup of balsamic sauteed kale and onions side dish

Balsamic sauteed kale and onions make a healthy, flavorful, and easy side dish for any occasion, from a weeknight meal to Thanksgiving dinner. Massaging kale tenderizes its leaves, while quick cooking retains most of the nutrients. Meat free, dairy free, gluten free, keto, Whole 30, nut free, soy free, vegan, vegetarian.

Prep Time 8 minutes
Cook Time 12 minutes
Total Time 20 minutes

Ingredients

  • 6 cups loosely packed kale leaves, well rinsed, torn into bite-size pieces (stems removed)
  • 2 garlic cloves, minced
  • 1 small onion or shallot, thinly sliced
  • Salt, pepper to taste
  • 1.5 tsp balsamic vinegar
  • Dash red pepper flakes (optional)
  • Avocado or grapeseed oil (or cooking spray)

Instructions

  1. Massage the torn kale leaves to soften them: rub the pieces together, knead them like dough, squeeze them until the kale reduces in volume and turns bright green.
  2. Preheat a large heavy-bottomed skillet or cast iron pan over medium heat. Slice onions or shallots while the skillet is heating. Add a splash of oil to the skillet (or spray it with cooking spray). Saute sliced onions or shallots, stirring often, until they soften and start turning golden brown, about 5-6 minutes.
  3. Increase the heat to medium high. Mix the minced garlic into the onions, and stir until it releases its aroma, about 30 seconds.
  4. Add torn kale leaves, mix briefly. Cover the pan with a lid, and let the kale "sweat" and reduce in volume, about 2 minutes. Remove the lid, sprinkle the kale with salt and pepper, mix well.
  5. Take the pan off the heat and immediately add a splash of balsamic vinegar. Toss the kale as the vinegar sizzles and starts evaporating. Make sure to get some of the vinegar reduction on all kale pieces. Taste and adjust seasoning.
  6. Serve right away sprinkled with red pepper flakes if desired.

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Nutrition Information:

Yield:

2

Serving Size:

1.5 cup

Amount Per Serving: Calories: 195Total Fat: 9gSaturated Fat: 1gTrans Fat: 0gUnsaturated Fat: 7gCholesterol: 0mgCarbohydrates: 22gFiber: 9gSugar: 7gProtein: 8g

Please note that the provided nutritional information data is approximate.

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