Vegan French Onion Lentils with Creamy Mashed Potatoes

These Vegan French Onion Lentils with Creamy Mashed Potatoes are a cozy, gluten-free comfort food dinner made with jammy caramelized onions, garlic, hearty lentils, and fresh herbs. This hearty vegan dinner is packed with plant-based protein, easy enough for weeknights, and perfect for chilly evenings.

This recipe is the ultimate cozy comfort food, and perfect as we head into Fall. Rich caramelized onions, earthy lentils, and thyme & rosemary are simmered together in a flavorful French onion-inspired sauce, then served over my fluffy dairy-free mashed potatoes.

Why You’ll Love This Recipe

• Rich French onion flavor. Slowly caramelized onions, fresh herbs, miso, and balsamic vinegar create a deeply savory, slightly sweet flavor inspired by classic French onion soup.
• Hearty and satisfying. Protein and fiber-rich lentils turn this cozy dish into a filling plant-based meal.
• Naturally vegan and gluten-free. It’s made entirely without meat, dairy, eggs, or gluten.
• Ultimate comfort food. The savory French onion lentils are especially delicious spooned over creamy mashed potatoes.
• Made with simple ingredients. Made with affordable pantry ingredients that are easy to find.
• Perfect for fall and winter. Warm, savory, and comforting, it’s an ideal dinner for chilly evenings.
• Great for meal prep. The lentils store and reheat perfectly, and the French onion flavor gets even better after sitting overnight.
• Versatile. Serve the lentils over mashed potatoes, creamy polenta, rice, baked potatoes, or alongside crusty gluten-free bread.

Ingredients

Vegan butter. Vegan butter adds richness and helps the onions caramelize beautifully while creating a silky, savory base for the lentils. It also makes the mashed potatoes extra creamy and flavorful. You may use olive oil instead of butter if desired.

Yellow onions. The onions are the star of this recipe. Cooking them low and slow allows their natural sugars to caramelize, creating the signature sweet, rich flavor that makes French onion dishes so irresistible.

Salt. Salt helps draw moisture from the onions, allowing them to soften evenly and caramelize more efficiently while enhancing the overall flavor of the dish.

Balsamic vinegar. A splash of balsamic vinegar adds subtle sweetness and acidity, helping balance the rich caramelized onions while creating even more depth of flavor.

Garlic. Fresh garlic complements the sweet onions without overpowering the classic French onion flavor.

Gluten-Free flour. A small amount of gluten-free flour lightly thickens the sauce, giving the lentils a rich, gravy-like consistency that’s perfect for serving over mashed potatoes.

Tomato paste. Tomato paste adds concentrated richness without making the dish taste tomato-forward. It simply enhances the savory flavors.

Fresh thyme. Thyme is one of the signature herbs used in French onion soup. Its earthy, woodsy flavor pairs perfectly with caramelized onions and lentils.

Fresh rosemary. Rosemary adds a subtle pine-like aroma and hearty flavor that complements the comforting, rustic feel of this dish. A little goes a long way.

Liquid aminos/gluten-free soy sauce (tamari). Liquid Aminos or Tamari soy sauce provides a rich, savory umami flavor while keeping the recipe completely gluten-free. It also adds beautiful color and depth to the sauce. I prefer using liquid aminos because there’s no added sugar or additives.

White miso paste. Instead of vegan Worcestershire sauce, white miso adds incredible depth, richness, and umami while keeping the ingredient list simple. Make sure it’s gluten-free!

Dijon mustard. Just a small amount of Dijon mustard brightens the flavors and adds a subtle tanginess that balances the richness of the onions and lentils.

Pure maple syrup. A touch of maple syrup is optional but helps round out the savory flavors by enhancing the natural sweetness of the caramelized onions.

Brown lentils. Brown lentils become tender while still holding their shape, making them perfect for this hearty meal. They’re also packed with plant-based protein and fiber, making this recipe satisfying and nourishing. I like this brand of dry brown lentils because they are certified glyphosate residue free and they come in plastic-free packaging!

Vegetable broth. Vegetable broth creates the flavorful cooking liquid for the lentils, allowing them to absorb every bit of the rich French onion-inspired flavor as they simmer. I suggest no salt added vegetable broth because the liquid aminios/soy sauce and miso paste will add a good amount of salt content.

Bay leaf. A bay leaf slowly infuses the lentils with subtle herbal flavor while they cook, adding another layer of savory complexity. Be sure to remove it before serving.

Black pepper. Freshly cracked black pepper adds gentle warmth and enhances the overall savory flavor of the dish without overpowering the caramelized onions.

Fresh thyme (for garnish). A sprinkle of fresh thyme just before serving adds color, freshness, and a final pop of classic French onion flavor.

Mashed Potatoes

Yukon gold potatoes. These potatoes mash beautifully into a creamy, buttery consistency without becoming gummy, making them the perfect base for the rich French onion lentils.

Unsweetened oat milk. Unsweetened oat milk creates light, creamy mashed potatoes without overpowering the flavor. Its naturally mild taste makes it an excellent dairy-free option.

Nutritional yeast. Nutritional yeast adds a subtle cheesy, buttery flavor to the mashed potatoes while contributing a boost of savory richness.

Garlic salt. Garlic salt provides mellow garlic flavor throughout the mashed potatoes, complementing the fresh garlic in the lentil mixture without being overpowering.

Products Used In This Recipe

How to Make Vegan French Onion Lentils

Step 1: Caramelize the onions

Heat the vegan butter or olive oil in a deep skillet over medium-low heat. Add the sliced onions and salt. Cook for 35–45 minutes, stirring every few minutes, until the onions are deeply golden, soft, and jammy. If they begin to stick, add a splash of water or broth and scrape up the browned bits.

Stir in the balsamic vinegar and garlic and cook for 1 minute. Sprinkle the flour over the onions and stir continuously for 1 minute.

Step 2: Build the lentil mixture

Whisk together the tomato paste, gluten-free soy sauce, white miso, Dijon mustard, and maple syrup. Spoon the paste-like mixture into the pan. Add the thyme and rosemary. Cook for another minute to deepen the flavor.

Add the vegetable broth.

Finally, add the lentils, bay leaf, and a generous pinch of black pepper. Stir well. Bring to a boil, then reduce the heat to low. Cover and simmer for 30–35 minutes, stirring occasionally, until the lentils are tender and most of the liquid has been absorbed.

Step 3: Prepare the mashed potatoes

Meanwhile, make the mashed potatoes. Boil the peeled and cubed potatoes until soft, about 15-20 minutes. You can tell the potatoes are done if you poke them with a fork and they are soft. Drain, add the potatoes back to the pot and add the plant milk, dairy-free butter, dairy-free sour cream or yogurt (if using), garlic salt and pepper to taste. Turn the heat to low and mash the potatoes with a potato masher or fork until you achieve your desired texture. Add a little bit more milk if you need to make them smoother, if you don’t like lumps.

Step 4: Assemble

Remove the bay leaf from the french onion lentils. Spoon a generous serving of mashed potatoes into each bowl and top with the French Onion Lentils. Finish with fresh thyme and cracked black pepper, if desired.

Storage

Store leftovers in an airtight container in the refrigerator for up to 4 days. The lentils actually become even more flavorful overnight, making this an excellent meal prep recipe. Freeze the lentil mixture separately for up to 3 months. Prepare fresh mashed potatoes when serving for the best texture.

Tips for Success

• Don’t rush the onions. The longer they caramelize, the deeper the flavor.
• Stir the lentils occasionally while simmering to prevent sticking.
• If the lentil mixture becomes too thick, add another splash of vegetable broth.
• If it’s too thin, simmer uncovered for a few extra minutes.
• Taste before serving and adjust the salt and pepper as needed.

Frequently Asked Questions

Can I use green lentils?

Yes! Green lentils work well and hold their shape similarly to brown lentils.

Can I make this ahead of time?

Absolutely. The lentils can be made several days in advance and reheated before serving over freshly made mashed potatoes.

What to Serve with French Onion Lentils (other than mashed potatoes)

Since the French Onion Lentils are rich, savory, and almost stew-like, they’re incredibly versatile. Here are some delicious serving ideas beyond mashed potatoes:

Grains

• Creamy polenta. The creamy cornmeal is fantastic with the rich onion gravy.
• Buttery white rice or brown rice.
• Wild rice blend for a nutty flavor.
• Quinoa for extra protein.

Vegetables

• Roasted garlic mashed cauliflower. Lighter than mashed potatoes, and a carb-conscious option but still comforting.
• Mashed sweet potatoes.
• Baked sweet potatoes stuffed with the lentils.
• Roasted mashed squash, like butternut squash or delicata squash.
• Acorn squash halves filled with the French Onion Lentils.
• Over spaghetti squash.
• Stuffed bell peppers. (Think Shepherd’s Pie Stuffed Peppers)
• Stuffed portabello mushrooms.

Pasta

• Gluten-free pappardelle.
• Gluten-free cavatappi.
• Gluten-free gnocchi (pan-fried first for extra texture). Check out my recipe for French Onion Gnocchi and add the lentils!

Bread

• Thick slices of toasted gluten-free sourdough.
• Gluten-free baguette.
• Gluten-free garlic bread.
• Open-faced Texas toast topped with the French Onion Lentils.
• Gluten-free biscuits.

Comfort Food Bases

• Baked potatoes loaded with French onion lentils.
• French fries or steak fries (think vegan poutine vibes).
• Hash browns.
• Crispy smashed potatoes.
• Savory pot pie filling topped with gluten-free puff pastry or pie crust.
• Lentil shepherd’s pie (like my easy Shepherd’s Pie recipe).
• Maybe even try hand pies using gluten-free pie dough.

If you’re looking for a cozy, nourishing dinner that’s packed with comforting flavor, these Vegan French Onion Lentils with Creamy Mashed Potatoes deserve a spot on your weekly or holiday menu. It’s simple enough for weeknights yet special enough to serve to guests.

Whether you’re craving comfort food during the colder months or simply looking for a hearty plant-based dinner the whole family will love, this recipe is one you’ll find yourself making again and again. If you love it, be sure to comment below in the comments section, as well as giving it a ⭐️⭐️⭐️⭐️⭐️ rating  so that others can discover this plant-based, protein-rich meal! Tag me on Instagram, Facebook, or Pinterest!

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