Step 1

Preheat oven to 350 degrees F (175 degrees C).

Step 2

Bring a large pot of lightly salted water to a boil. Cook spaghetti in the boiling water, stirring occasionally until cooked through but firm to the bite, about 12 minutes. Drain.

Step 3

Heat a large skillet over medium-high heat. Cook and stir beef in the hot skillet until browned and crumbly, 5 to 7 minutes; drain and discard grease. Transfer to a bowl and mix spaghetti sauce into ground beef.

Step 4

Place half the slices of butter into the bottom of a 9x13-inch casserole dish. Spread half the spaghetti into the dish. Mix cottage cheese, cream cheese, and sour cream together in a bowl; spread mixture over spaghetti. Layer remaining spaghetti over creamy mixture. Top with remaining pats of butter.

Step 5

Pour ground beef mixture over spaghetti and spread to cover casserole.

Step 6

Bake in the preheated oven for 30 minutes. Spread Cheddar cheese over casserole and continue baking until cheese has melted and is lightly browned, about 15 more minutes.