Heat your oven to 375°F (190°C) so it is ready when you are. Wash the peppers, slice them in half from stem to base, and remove the seeds and white ribs. Brush the insides lightly with olive oil and place them cut side up in your baking dish.
Cover the dish with foil and bake the empty peppers for about 10 minutes. This quick step softens them so they finish cooking at the same time as the filling. I never skip it because it stops the peppers from staying crunchy.
In a large bowl, combine the cottage cheese, cooled rice, egg, garlic, Italian seasoning, black pepper, and salt. Stir in half of the mozzarella and all of the parmesan. Mix until everything looks evenly combined and thick, not runny.
Take the peppers out of the oven and spoon the filling into each half. Press it down gently and pile it a little high in the center. Don't worry about being neat because the cheese will melt and hide any gaps.
Spoon a little marinara over the filling in each pepper. Sprinkle the remaining mozzarella on top for that gooey, melty finish. A thin layer of sauce is enough, since too much can make the filling slide out.
Bake uncovered for 25 minutes, or until the cheese is bubbly and the edges turn golden. The peppers should feel tender when you poke them with a fork. For extra color, broil on high for 1 to 2 minutes at the very end.
Let the peppers rest for about 5 minutes so the filling sets. Top them with torn fresh basil and a little extra black pepper. Serve warm while the cheese is still stretchy and creamy.