Preheat the oven. Take tomatoes, bell pepper, and onions in a baking pan. Add olive oil, salt, red pepper flakes, black pepper powder, Italian seasoning, and garlic. Mix them well.
Place the block of feta in the center. Drizzle remaining olive oil on the cheese, red pepper flakes, and Italian seasoning. Bake until the tomatoes have burst and are nice and juicy.
Cook the pasta according to the package instruction. Once cooked, reserve a cup the starchy pasta water to use later. Drain then keep aside.
Mash the cheese and mix everything together. Immediately mix the spinach. Add pasta, basil, and olives to the tomato-feta mixture and stir until well combined.