In a medium pan, melt the butter/oil on medium. Add the flour and whisk to form a roux or thick paste. Cook 1-2 minutes until it is just about to change color.
Add almond milk, whisk as you add, making sure there are no lumps. Add the nutmeg, black pepper and salt to taste.
Remove from heat after the sauce has thickened into a smooth gravy-like velvety texture. (Use 1.5 cups almond milk for thicker sauce. I used 2 cups as the sauce will thicken further during baking)
Lasagna
Layer some bechamel, top with Lasagna sheets. Top with thin slices of cauliflower. Sprinkle a little salt, (sprinkle chili flakes and garlic powder.Optional)
Drizzle some more bechamel sauce. Layer Lasagna sheets. Top the sheets with cooked Sweet potato slices(or thin raw slices). Sprinkle some dried thyme or parsley.
Drizzle a little bechamel (or marinara). Top with Lasagna sheets.
Spread the rest of the bechamel. Top with Bread crumbs mixed with dried herbs of choice, nutritional yeast, salt and pepper, or Cheese(vegan mozzarella shreds or parmesan or ground cashew/almond +nutritional yeast). Cover the pan with aluminium foil.
Bake in preheated 360 degrees F / 180ºc for 50 minutes to an hour. Take itout of the oven. Remove foil. Let sit for 5 minutes before serving.
Notes
Variations: You can add 1-2 layers of Marinara or Bolgonese sauce, some non dairy cheese(mozzarella or herbed Tofu Ricotta) and lasagna sheets.Nutritional values based on one serving