Gather lasagne sheets, ground meat or vegetables, onion, garlic, tomato sauce, tomato paste, olive oil, salt, pepper, Italian herbs, ricotta or béchamel, mozzarella, and Parmesan
Preheat the oven to 375°F
Heat olive oil in a pan
Sauté chopped onion and garlic
Add ground meat or vegetables
Cook until browned or softened
Stir in tomato paste, tomato sauce, salt, pepper, and herbs
Simmer the sauce
Mix ricotta with salt, pepper, and Parmesan or prepare béchamel
Spread a layer of sauce in a baking dish
Add a layer of lasagne sheets
Spread a layer of ricotta or béchamel
Add a layer of sauce
Sprinkle mozzarella
Repeat the layers until the dish is full
Finish with sauce, mozzarella, and Parmesan on top
Cover with foil
Bake for 30 minutes
Remove foil
Bake for 15 to 20 minutes more until golden and bubbling
Let it rest before slicing
Serve warm