01 - Preheat oven to 375°F. Unroll the pie crust and gently press it into a 9-inch pie dish. Trim any overhanging dough and flute the edges decoratively. Prick the bottom lightly with a fork to prevent puffing. Set the lined dish aside.
02 - Heat olive oil in a large skillet over medium heat. Add the ground beef and cook, breaking it apart with a wooden spoon, until evenly browned and no pink remains, approximately 5 to 7 minutes. Drain excess fat from the pan if needed.
03 - Add the diced onion and minced garlic to the browned beef. Sauté until the onion is softened and translucent, about 3 minutes. Pour in the marinara sauce, dried oregano, salt, and pepper. Stir to combine and let the sauce simmer gently for 5 minutes. Remove from heat and set aside.
04 - In a medium mixing bowl, combine the ricotta cheese, egg, 1 cup of the mozzarella, Parmesan, chopped basil, and red pepper flakes. Stir until the mixture is smooth, creamy, and well blended.
05 - Spread half of the meat sauce evenly across the bottom of the prepared pie crust. Drop spoonfuls of the ricotta mixture over the sauce layer and gently spread it into an even layer. Top with the remaining meat sauce, then sprinkle the remaining 1 cup of mozzarella evenly over the surface.
06 - Loosely tent the pie with aluminum foil and place it in the center of the oven. Bake for 30 minutes, then carefully remove the foil and continue baking for an additional 15 minutes, or until the cheese is deeply golden and bubbling.
07 - Remove the pie from the oven and allow it to rest for 10 minutes before slicing. This resting period helps the layers set and ensures clean, gooey portions. Serve warm, garnished with additional fresh basil if desired.