French Onion Shepherd’s Pie

You know that cozy, stick-to-your-ribs feeling you get from a great shepherd’s pie? Now imagine that comfort upgraded with caramelized onions, French lentils, and a silky cauliflower–potato mash that refuses to be boring. I made this recipe on a rainy Tuesday when I felt like feeding a crowd and not spending my evening chained to the stove. Spoiler: everyone asked for seconds.

This recipe highlights sweet, jammy onions, meaty French lentils, and a light but creamy mash that keeps things comforting without feeling heavy. I’ll walk you through every step, share my favorite shortcuts and swaps, and sprinkle in a little sarcasm because cooking should be fun, not stressful. Ready?

Why You’ll Love This Recipe

• Comfort without the heaviness — the cauliflower cuts down on starch but keeps the mash creamy.
• Deep, sweet flavor from slow-caramelized onions that act like the soul of the dish.
• Plant-forward and satisfying — lentils give a meaty texture and protein, perfect for vegans and omnivores alike.
• Make-ahead friendly — this pie reheats beautifully and freezes well for busy weeks.
• Impressive but manageable — it looks fancy, but you can totally handle it.

Ingredients You’ll Need

• 2 tablespoons olive oil, plus extra
• 3 lbs yellow onions, peeled and sliced into half moons
• sea salt and ground black pepper, to taste
• 1 tablespoon thyme leaves, minced
• 1 bay leaf
• 1 clove of garlic, minced
• 1 tablespoon tomato paste
• 1 ½ cups French lentils, rinsed
• 1 ½ tablespoons sherry/balsamic vinegar
• 1 ½ tablespoons gluten-free tamari soy sauce
• 5 cups vegetable stock, plus extra
• 2 cups water
• 2 cloves of garlic, peeled and smashed
• 1 ½ lbs Yukon gold potatoes, peeled and chopped
• 4 cups cauliflower florets (from approximately ½ a large head)
• 4 tablespoons vegan butter, at room temperature
• ½ cup unsweetened non-dairy milk
• 1 tablespoon nutritional yeast
• sea salt and ground black pepper, to taste

How to Make (Step-by-Step)

Sauté the onions (this is the stage that wins hearts)

Heat a large soup pot over medium heat. Pour in the olive oil and swirl it around. Add all the sliced onions. You should hear a moderate sizzle. Sauté the onions, stirring often, until they just start to soften on the edges. Lower the heat slightly.

Keep cooking and stirring the onions occasionally until they turn light golden brown, jammy, and super sweet. Don’t aim for fully dark caramelization; you want deep sweetness without bitterness. This step will take 45 minutes to an hour. Add splashes of water if the onions start to dry up or stick.

Build the French onion base

Increase the heat back to medium. Add the thyme, bay leaf, and minced garlic and stir until fragrant, about 30 seconds. Add the tomato paste and stir for about a minute to deepen the flavor. Add the rinsed lentils and stir to coat. Pour in the sherry/balsamic vinegar and tamari. Scrape up any browned bits on the bottom with your spoon — those bits hold good stuff.

Season with salt and pepper. Add the vegetable stock and stir. Cover the pot and bring it to a boil. Lower the heat and simmer until the lentils become tender, about 25–30 minutes. Keep just enough liquid to surround the onions and lentils; add more stock if needed. Remove the bay leaf.

Transfer to your baking dish

Allow the French onion base to cool slightly. Transfer it to a large (12-inch) oven-safe skillet or baking dish and spread it out. Set aside while you make the mash.

Make the creamy cauliflower–potato mash

Pour the 2 cups water into a large soup pot and bring to a boil. Toss in the smashed garlic cloves. Place the potatoes and cauliflower into the pot (or use a steamer insert). Keep a strong simmer and close the lid. Steam until the potatoes are fork-tender, about 20 minutes.

Drain the vegetables and return them to the pot. You can keep the garlic for flavor or discard it — your choice. Add the vegan butter, non-dairy milk, nutritional yeast, and lots of salt and pepper. Use a hand masher to mash until smooth and creamy. Taste and adjust seasoning.

Assemble and bake

Preheat the oven to 375°F. Smooth the lentil-onion base, then dollop the mash on top. Spread the mash to cover evenly. Drizzle the top with a little olive oil and pinch on extra salt and pepper.

Bake for 25 minutes, until bubbly and hot. If you like a browned top, broil for a minute or two, but watch it like a hawk. Remove from the oven and let rest 5 minutes before serving in shallow bowls.

Pro Tips for the Best Results

• Caramelize patiently. Low and slow gives you that sweet jammy onion flavor.
• Taste as you go. Adjust salt, vinegar, and tamari to balance sweet and savory.
• Use Yukon golds. They mash creamy without needing too much liquid.
• Steam, don’t boil. Steaming keeps cauliflower fluffy and less waterlogged.
• Make ahead. Assemble the day before and bake when guests arrive.
• Freeze-friendly. Cool completely, wrap tightly, and freeze up to 3 months.

Fun Variations & Topping Ideas

Variations:

• Swap proteins: Use cooked minced mushrooms or chopped walnuts with lentils for extra texture.
• Make it gluten-free: This recipe already uses tamari; ensure your stock and tomato paste state gluten-free.
• Spice it up: Stir in a pinch of smoked paprika or cayenne for a kick.

Toppings:

• Breadcrumb crust: Mix gluten-free breadcrumbs with olive oil and sprinkle on top before baking for crunch.
• Herb garnish: Scatter chopped parsley or chives for brightness.
• Cheesy finish: Sprinkle vegan parmesan or nutritional yeast before serving.

Storing and Reheating

Store leftovers in an airtight container in the fridge for up to 4 days. Reheat individual portions in the microwave for 2–3 minutes, stirring halfway. Reheat a whole pie in a 350°F oven for 20–30 minutes, covered with foil for the first 15 minutes to prevent drying. To reheat from frozen, thaw overnight in the fridge then bake as above.

Frequently Asked Questions (FAQ)

Can I substitute brown or green lentils?

Yes. Brown or green lentils work but note they soften differently. French lentils hold their shape best, so they give a meatier texture. If you use other lentils, watch cooking time.

Can I make this without dairy or butter? Absolutely.

I use vegan butter and non-dairy milk in the mash. The recipe remains rich and creamy without dairy.

How do I prevent a watery mash?

Steam the cauliflower and potatoes instead of boiling to limit water absorption. Drain thoroughly and mash while hot. Add non-dairy milk gradually to control consistency.

Can I prep parts ahead of time?

Yes. You can caramelize the onions and cook the lentils 1–2 days ahead; store chilled. Make the mash ahead and rewarm before assembling. This trick saves time when guests arrive.

Will this freeze well?

Yes. Cool completely, then wrap tightly and freeze up to 3 months. Thaw in the fridge overnight before reheating.

Conclusion

This French Onion Shepherd’s Pie with Lentils and Creamy Cauliflower Potato Mash gives you deep, caramelized flavor, satisfying lentil heft, and a lighter, dreamy mash that still hugs your soul. It works for weeknights, dinner parties, and those “I-feel-like-comfort-food-but-want-to-eat-clean” days. Try it once and I bet it becomes a regular.

If you want another plant-based take or inspiration from a trusted source, check out this excellent recipe for a similar concept from French Onion Shepherd’s Pie w/ Cauliflower Mash | The First Mess — it inspired some of my swaps.

Before you go: leave a comment and rating if you try it. Did you broil the top to golden perfection or go full rustic? I want to know. IMO, leftovers taste even better the next day. FYI: I absolutely will judge you if you skip the caramelized onions.