Add all the ingredients to a pan at medium heat. Cover and cook for 11 to 12 minutes. Mix, Taste and adjust salt and spice. Cook covered for another few minutes if the lentils are not well done.
Assemble the sandwich:
Spread vegan butter or brush olive oil on the bread slices.
Layer alfredo sauce, then spinach. Add the lentil filling and spread to cover the slice. Add pasta sauce, alfredo sauce, salt, pepper.
Add some pepita parmesan (optional) or sprinkle nutritional yeast and italian herbs. Add vegan cheese shreds to make it more sticky (optional). Place another slice on top and grill.