Preheat oven to 350 degrees. In a large sauté pan, heat olive oil over medium heat. Add sausage and crumble as it cooks with a wooden spoon. Cook about 8 minutes, or until there is no pink left. Turn off heat and drain sausage on a paper towel lined plate.
Meanwhile, bring a large pot of salted water to a boil. Cook pasta until al dente or according to the package directions. Drain water and pour noodles in a large mixing bowl.
Add cooked sausage, sour cream, cottage cheese, half the marinara sauce, and one cup mozzarella and stir until combined.
Pour mixture into a 9 by 13 casserole dish. Top with last cup of marinara and last cup of cheese. Bake for 30 minutes or until cheese is bubbly. Let cool 5-10 minutes before serving.
Notes
Katie’s Tips:*I reserve a ½ cup of pasta water to thicken/adjust the sauce.*I always cook the pasta one minute under the recommended time because thenoodles will cook a little more in the oven and I only like eating pasta cooked aldente- with a little bite.*To get the cheese bubbly and light brown, I turn on the broiler after baking and put the casserole dish back in for 2 minutes. Watch closely so it doesn't burn!