Spaghetti Squash Casserole in the Shell

1 spaghetti squash, halved and seeded
1 pound lean ground beef
1/2 cup finely chopped onion
1/2 cup minced bell pepper
1 clove garlic, minced
1 teaspoon dried basil
1 teaspoon dried oregano
1/2 teaspoon salt
1/4 teaspoon ground black pepper
1 (14.5 ounce) can diced tomatoes, drained
1/3 cup shredded Cheddar cheese

Preheat oven to 375 degrees F.
Place squash in baking pan; pour in enough boiling water to come 1/2-inch up the sides of dish.
Bake in the preheated oven until squash is tender, 40 to 45 minutes.
Remove from oven; cool until easily handled, 7 to 10 minutes.
Reduce oven to 350 degrees F.
Scoop out squash; separate strands with a fork. Reserve shells.
Cook beef, onion, and bell pepper in a skillet over medium heat until the meat is no longer pink,
about 5 minutes; drain.
Stir in garlic, basil, oregano, salt, and pepper; cook and stir until fragrant, about 2 minutes.
Add tomatoes and cook until warmed through, about 2 minutes.
Stir in squash; cook until liquid has evaporated, about 10 minutes.
Fill squash shells with squash mixture using a slotted spoon; place in a shallow baking pan.
Bake in the preheated oven until flavors combine, about 15 minutes.
Sprinkle with Cheddar cheese; bake until cheese is melted, about 5 minutes.