Heat some oil in a pot and add the onion, garlic, and mushrooms. Simmer for a short time and then add the ground beef. Continue simmering while adding salt, chili flakes, and oregano. When the ground beef is cooked, add the marinara sauce and continue on a low flame.
Mix the ricotta cheese with the eggs and grated Parmesan.
Lay the lasagna noodles on the bottom of a spring-form baking pan. Pour on 1/3 of the sauce and add another layer of lasagna noodles. On this layer, add the ricotta cream and cover it with pepperoni slices. Then continue as follows: lasagna noodles, sauce, lasagna noodles, ricotta, pepperoni, lasagna noodles, sauce, mozzarella, pepperoni.
Bake it for 60 minutes at 340 °F.