creamy pasta bake

1 jar (30 oz.) spaghetti sauce
1 pkg. (16 oz.) rainbow rotini, cooked and drained
1 1/2 c. sour cream
1 pkg. (10 oz.) frozen chopped spinach, thawed and drained
1/2 c. grated Parmesan cheese

Heat oven to 375. Mix all ingredients. Spoon into 13x9" baking dish. Bake 25 minutes.

So easy it's embarrassing!