One-Pan Smoky Veggie Lentil Lasagne

Rainy Sunday afternoons were made for dishes like this. I first attempted a one-pan lasagne during a particularly dreary February, tired of washing multiple pots while craving something deeply comforting. The smoky paprika was actually a happy accident—I'd grabbed it instead of regular paprika in my dimly lit cupboard, and that mistake transformed the entire dish into something far more interesting than my usual lasagne.

Last winter, my sister dropped by unexpectedly while this was bubbling away in the oven. She kept asking what meat I'd used, certain no vegetable dish could smell this deeply savory. Watching her face when I told her it was just lentils and vegetables was absolutely priceless—she went home with the recipe written on the back of a grocery receipt.

Ingredients

• 2 tbsp olive oil: A generous amount helps the vegetables soften and develop those lovely golden edges
• 1 large onion: The foundation of flavor, so take time to chop it finely
• 2 garlic cloves: Freshly minced is best here—jarred garlic can taste bitter
• 1 medium carrot: Adds subtle sweetness and balances the smoky notes
• 1 red bell pepper: Brings sweetness and vibrant color to every layer
• 250 g mushrooms: Chestnut mushrooms have more flavor than white ones
• 2 medium courgettes: Dice them evenly so they cook at the same rate
• 1 tsp smoked paprika: This is the star ingredient—do not substitute regular paprika
• 1 tsp dried oregano: Use your fingers to crumble it and release the oils
• 1/2 tsp dried thyme: Earthy and aromatic, perfect for long-simmered sauces
• 1/2 tsp chili flakes: Just a gentle warmth that makes everything else pop
• 1 tbsp tomato paste: Concentrated umami that deepens the sauce color
• 400 g chopped tomatoes: Quality matters here—choose a brand you'd actually eat on toast
• 1 tbsp soy sauce: Sounds unusual but adds the same savory depth that anchovies do to traditional sauces
• 125 g dried red lentils: They'll melt into the sauce, making it thick and creamy
• 500 ml vegetable stock: Use hot stock for faster cooking
• 40 g unsalted butter: Essential for a proper béchamel
• 40 g plain flour: Plain flour gives the smoothest results
• 600 ml whole milk: Warmed slightly prevents lumps from forming
• 1/4 tsp ground nutmeg: The secret ingredient that makes white sauce taste like a restaurant made it
• 60 g grated mature cheddar: Mature cheese has more flavor, so you need less
• 9–12 no-boil lasagne sheets: No-boil sheets absorb the sauce perfectly as they cook
• 50 g grated mozzarella: For that golden, bubbling top layer

Instructions

Get your oven ready:

Preheat to 200°C, letting it come fully to temperature while you prep

Build the flavor base:

Heat oil in your ovenproof pan and soften onion and garlic for 2 minutes until fragrant

Add the vegetables:

Cook carrots, peppers, mushrooms, and courgettes for 5 to 6 minutes until they start to color

Bloom the spices:

Stir in smoked paprika, oregano, thyme, chili flakes, and tomato paste, cooking for 1 minute until the tomato paste darkens

Create the sauce:

Add tomatoes, soy sauce, lentils, and stock, then simmer covered for 15 to 20 minutes until lentils are tender and sauce is thick

Make the béchamel:

Melt butter in a separate pan, whisk in flour for 1 minute, then gradually add milk, stirring until thickened

Season the white sauce:

Remove from heat and stir in nutmeg, cheese, salt, and white pepper

Layer it up:

Remove half the veggie sauce, spread a third of béchamel over what remains, then add pasta sheets

Build the middle layer:

Spread half the reserved sauce, another third of béchamel, and more pasta sheets

Finish with flair:

Top with remaining sauce, final pasta layer, rest of the béchamel, and scatter mozzarella

Bake covered:

Cover loosely with foil and bake for 25 minutes

Golden finish:

Remove foil and bake for 10 to 15 minutes until bubbly and gorgeous

Patience pays off:

Let stand for 10 minutes before serving—this is crucial for clean slices

Save

This recipe has become my go-to for new parents and anyone needing a meal that feels like a hug. There's something deeply satisfying about serving people a dish that looks complicated but came from one humble pan.

Make It Your Own

The beauty of this recipe is how it adapts to what you have. Spinach works brilliantly added to the veggie mix, and a splash of red wine transforms it into something dinner-party worthy.

Perfect Pairings

A sharp green salad with a mustardy dressing cuts through the richness beautifully. Garlic bread is non-negotiable in my house—you need something to mop up that smoky sauce.

Getting Ahead

You can assemble the entire lasagne up to 24 hours ahead and keep it refrigerated. Add 5 to 10 minutes to the covered baking time if cooking from cold.

• The flavors actually improve overnight if you have leftovers
• This freezes beautifully for up to three months
• Thaw overnight before reheating at 180°C

Save

There's something magical about pulling that foil off and seeing those golden bubbles. This is comfort food at its absolute best.

Recipe FAQ

→ Can I make this vegan?

Absolutely. Replace dairy butter with plant-based alternative, use oat or soy milk, and choose vegan cheese varieties. The lentils provide excellent protein, making it a substantial plant-based main.

→ Why use red lentils instead of green?

Red lentils cook faster and break down slightly, creating a thicker, more cohesive sauce that holds layers together beautifully. They also absorb the smoky paprika flavor exceptionally well.

→ Do I need to pre-cook the lasagne sheets?

No-boil sheets are designed to cook in the oven. The moisture from the vegetable sauce and béchamel softens them perfectly during baking. If using traditional sheets, par-boil for 3-4 minutes first.

→ Can I prepare this ahead?

Yes. Assemble completely, cover tightly, and refrigerate for up to 24 hours before baking. Add 10-15 minutes to baking time if cooking from cold. You can also freeze assembled (unbaked) for up to 3 months.

→ What gives the smoky flavor?

Smoked paprika is the key ingredient. Don't skip it—it provides that distinctive, aromatic depth. A splash of soy sauce also adds umami richness that complements the smokiness beautifully.