In large bowl mash lentils coarsely (potato masher works well), stir in egg, cooked mushroom, mixture, rolled oats, Parmesan cheese, nuts, salt and pepper to taste.
Shape into four (3/4 inch/2 cm thick) patties
Cook patties in lightly greased non-stick fry pan or on a greased grill over medium-high heat, 3-4 minutes per side or until golden brown.