Cook and shred your spaghetti squash, or cook and drain your pasta of choice.
In a skillet, cook and drain the ground beef. Add the bell peppers, onions, and mushrooms and let them cook until softened.
Add the marinara sauce and spices and put it aside.
In a small bowl, combine the butter, cream cheese, sour cream, and half the parmesan and mix.
Toss the spaghetti squash into the cream cheese mixture.
Preheat your oven to 350 degrees.
Layer a small amount of the marinara sauce into the bottom of a casserole dish. Then put a layer of the spaghetti squash. Top with a layer of mozzarella and parmesan. Repeat until the dish is filled and sprinkle the remaining cheese on top.
Bake in the preheated oven for about 30 minutes or until the cheese starts to bubble and gets slightly golden.
Allow it to cool for a few minutes before serving and enjoy!