Spray the slow cooker insert with non-stick spray to prevent sticking and set aside.

Combine ricotta cheese, eggs, grated Parmesan, salt, basil, and pepper in a bowl and mix until creamy.

Pour a thin layer of marinara sauce at the bottom of the slow cooker to prevent sticking.

Spread the uncooked gluten-free penne over the marinara layer evenly.

Dollop portions of the ricotta mixture over the pasta layer and press down gently.

Sprinkle a generous layer of shredded mozzarella cheese atop the ricotta mixture.

Continue layering with marinara sauce, gluten-free penne, ricotta mixture, and mozzarella cheese for a total of three layers.

Pour any remaining marinara sauce over the final layer of mozzarella cheese followed by more mozzarella and Parmesan for extra cheesiness.

Cover and cook on high for 2.5 hours, checking for doneness around the two-hour mark.

Let sit for about 10 minutes after cooking before serving.