– While pasta cooks, combine marinara sauce, canned diced tomatoes, cream cheese, Italian seasoning, and garlic powder in a large bowl. Stir until well combined.
– Pour half the pasta mixture into the prepared pan. Smooth the top. Spread the sour cream over the pasta. If ½ cup sour cream isn't enough, add up to one cup more. Sprinkle with 1 cup of shredded cheese.
– Layer the remaining pasta mixture in the pan then sprinkle the rest of the shredded cheese over the top.– Bake uncovered for 30-40 minutes, or until bubbly and cheese is completely melted.