Preheat your oven to 375°F and boil about 10 cups of water for your pasta.
Add the mushrooms and onions to a large pan over medium heat with olive oil, salt, pepper, and crushed red pepper (optional). Cook until the mushrooms shrink and the onions turn translucent—about 5 minutes.
1 large yellow onion, diced, 2 tablespoons olive oil, ¼ teaspoon salt, ¼ teaspoon black pepper, ¼ teaspoon crushed red pepper, 8 ounces mushrooms, chopped
Once water is boiling, cook pasta until al dente, according to the directions on the box (usually about 6-10 minutes). Strain and set aside to dry completely.
16 ounces Penne Rigate
Add the marinara sauce to the mushrooms and onions to cook off any excess liquid in the sauce. Turn the heat source down to low. and stir frequently to avoid splatter.
24.5 ounces marinara or spaghetti sauce
Once your sauce thickens, add the cream cheese, shredded Italian blend cheese, and minced garlic and stir over low heat to combine.
4 cloves garlic, minced, 4 ounces cream cheese, 8 ounces Italian shredded cheese blend
Add the cooked pasta to the sauce and remove it from heat. Stir until the pasta is coated.
Transfer the pasta to a 9 x 13-inch glass baking dish. Top with an even, thin layer of mozzarella.
4 ounces shredded mozzarella
Bake for 25 minutes or until the cheesy top is golden brown. Garnish with fresh basil and enjoy with family and friends, or keep for up to 5 days in the refrigerator.
1 handful Fresh basil for garnish