Preheat oven to 375°F. Lightly grease a 9-inch pie dish with olive oil.

In a skillet over medium heat, cook ground beef, green pepper, and onion for about 10 minutes, until beef is browned. Stir in pasta sauce, chili powder, salt, and pepper. Simmer for 6 minutes, stirring occasionally.

Cook spaghetti according to package instructions. Drain and place into the prepared pie dish.

In a small bowl, whisk together eggs and cottage cheese until well blended. Spread this mixture evenly over the spaghetti in the dish. Top with beef mixture, then sprinkle with shredded mozzarella.

Bake for 35 minutes, or until the center is set and top is golden. Let stand for 5 to 10 minutes before slicing.