In a large oven-safe pan, combine the uncooked pasta, vegetable broth, bell peppers, garlic powder, Italian seasoning, salt, and pepper.
Stir everything together and bring to a simmer over medium heat.
Once simmering, reduce the heat and let it cook for 10 minutes, stirring occasionally.
Remove from heat and stir in the spinach and half of the cheese.
Top with the remaining cheese and transfer the pan to the oven.