Preheat oven to 375°F (190°C).
Heat olive oil in a skillet over medium heat.
Add ground beef and cook until browned.
Stir in marinara sauce, Italian seasoning, garlic powder, salt, and black pepper.
Simmer the meat sauce for 5 minutes.
Remove skillet from heat and mix in ricotta cheese.
Place bell pepper halves in a baking dish.
Spoon the meat mixture evenly into each pepper.
Top with mozzarella and Parmesan cheese.
Bake uncovered for 25 minutes until peppers are tender and cheese is melted.
Garnish with fresh basil and serve warm.