01 -
Heat olive oil in a large skillet over medium-high heat. Add ground beef, diced onion, and sliced mushrooms. Cook until beef is completely browned and vegetables are tender, about 8-10 minutes. Drain any excess grease.
02 -
Lower heat to medium and stir in oregano, marinara sauce, salt, pepper, and red pepper flakes. Let simmer for 5 minutes, then remove from heat.
03 -
Bring a large pot of salted water to boil. Cook lasagna noodles according to package directions until al dente. Drain and rinse with cold water to stop cooking.
04 -
In a mixing bowl, combine ricotta cheese, Parmesan cheese, and eggs. Stir until smooth and well blended. Season with salt and pepper.
05 -
Preheat oven to 375°F. Grease a 9x13 inch baking dish. Spread a thin layer of meat sauce on bottom. Layer with noodles, ricotta mixture, mozzarella cheese, pepperoni slices, and more meat sauce. Repeat layers until all ingredients are used, ending with cheese on top.
06 -
Cover tightly with aluminum foil and bake for 35 minutes. Remove foil and bake 10 more minutes until cheese is golden. Let rest 10-15 minutes before cutting. Garnish with chopped parsley before serving.