Preheat the oven according to package directions. I cooked mine at 180°C (gas mark 5).
Spread a thin layer of white sauce on the bottom of a baking dish. Place 4 lasagne sheets over the thin layer of the white sauce.
Spread 1/3 of the lentil filling, then about 1/3 of the white sauce, then top with another layer of 4 lasagne sheets. Repeat these steps twice, but the second time you don’t have to top with a layer of noodles. Sprinkle the top with the vegan cheese.
I baked mine for 40 minutes but the baking time can vary depending on your lasagne sheets.
When it's cooked, take out from the oven and leave to rest for at least 10 minutes before serving. It will cut nicely in portions after the rest. Sprinkle the top with some parsley (optional).