24ouncesmeatballs (I used frozen cooked ones)see note
1tablespoonolive oil
1/2mediumonionchopped
3clovesgarlicminced
3cups (a 24 oz. jar)marinara sauce
Salt & pepperto taste
2cupsshredded mozzarella cheese
Instructions
Preheat the oven to 375F and move the rack to the top third of the oven.
Cook the noodles for a minute or two less than the package instructions suggest, then drain them and transfer to a 9x13 casserole dish.
Meanwhile, add the olive oil and onion to a skillet over medium-high heat. Cook for 4-5 minutes.
Stir in the garlic and cook for about 30 seconds.
Add in the marinara sauce and meatballs and heat through. Important: if using frozen meatballs, it's important to cook them until thawed (depending on the size/type of meatballs, this may take 8-10+ minutes). Simmer over medium heat (or lower if it's bubbling too much) and stir occasionally. Break a meatball in half to ensure that it's fully thawed.
Pour the skillet contents into the casserole dish and add half the cheese and toss together (I also add some salt & pepper at this point), then spread it out evenly.
Top the casserole with the remaining cheese and bake, uncovered, for 10-15 minutes or until it's hot and bubbly. Optional: broil it for a few minutes (watch it so it doesn't burn) to brown the cheese.
Notes
For convenience sake, I like to use pre-made frozen cooked meatballs. Use as many/few as you like. 24 oz. of them made quite a lot of casserole, so you could even use half the amount if you're only feeding 4 people, for example. Thawed meatballs or fresh homemade meatballs will work too (any kind of meatballs will be fine as long as they're already cooked or you may need to adjust cooking time to ensure they're a safe internal temperature of 160F).