Bring 2 cups of water to a boil.
Add the lentils and salt, and simmer for 30 minutes or until the lentils are soft.
Drain and let cool, then mash with the back of a fork or a masher.
Add the mushrooms, onion, garlic, oats, cheese, parsley, basil and pepper, and combine. Adjust the salt if necessary, then add the beaten egg, and combine.
Allow the mixture to rest approximately 5 minutes in order for the textures to blend. Form into 8 patties, and place on a baking sheet sprayed with non-stick cooking spray.
Bake in a 350° oven for 30 minutes. Carefully flip the burgers once to allow the other side to brown.
Serve on buns with your favorite toppings.