01 - Preheat oven to 375°F. Coat a 2-quart (10x7 inch) casserole dish with nonstick spray. Arrange a foil-lined baking pan on the lowest rack to catch possible drips.
02 - In a large skillet over medium heat, brown Italian sausage, breaking into small crumbles. Once fully cooked, use a slotted spoon to transfer sausage to a bowl, reserving 1 tablespoon of drippings in the skillet.
03 - Add butter and minced garlic to retained sausage drippings over medium-low heat. Sauté for 30 seconds or until aromatic. Whisk in heavy cream slowly to blend with the butter. Stir in red pepper flakes and black pepper. Simmer on low heat, whisking periodically, until mixture slightly thickens, about 3-5 minutes.
04 - Whisk grated parmesan cheese into the cream until smooth. Taste and adjust salt, pepper, and additional red pepper flakes as desired.
05 - Boil a large pot of salted water. Cook cheese-filled ravioli according to package instructions. Drain thoroughly.
06 - Spread 1/3 cup of Alfredo sauce onto the base of the prepared casserole dish. Arrange half the ravioli in an even layer, followed by half the sausage, half of the Alfredo sauce, and half of the mozzarella cheese. Repeat layering with remaining ravioli, sausage, sauce, and cheese.
07 - Sprinkle Italian seasoning and extra red pepper flakes to taste across the surface. Cover with foil lightly coated with nonstick spray to prevent sticking. Bake for 30 minutes, then remove foil and bake an additional 10-15 minutes until bubbling and golden at the edges.
08 - Allow lasagna to rest for 10-15 minutes before slicing to ensure clean servings.