Start by slicing your eggplants and sprinkling them with salt. Let them sit for 15 minutes, then pat dry. This step prevents bitterness and excess moisture from making your moussaka soggy. I like to lightly brush them with olive oil before roasting.
In a pan, sauté onions, garlic, and red bell pepper until soft. Add crushed tomatoes, tomato paste, lentils, and spices. Let it simmer for 10–15 minutes until thickened. I always taste and adjust salt and pepper at this stage—it makes a huge difference.
In a saucepan, melt butter and whisk in flour to make a roux. Slowly add milk while stirring continuously to prevent lumps. Add grated Parmesan, nutmeg, salt, and pepper, then simmer until thick and creamy.
In your baking dish, layer roasted eggplant slices, then half the vegetable-lentil sauce. Repeat the layers and top with the béchamel sauce. I find that spreading it evenly with a spatula ensures a beautiful golden top.
Bake in a preheated oven at 375°F (190°C) for about 35–40 minutes until the top is golden and bubbly. Let it cool for 10 minutes before slicing—it helps the layers set beautifully.