Ingredients:
1 box uncooked penne pasta
6 cups canned marinara or spaghetti sauce
3 cups of shredded mozzarella cheese, divided
1 cup grated parmesan cheese, halved
Instructions:
Grease a large oval slow cooker with either non stick spray or a thin layer of oil to help prevent sticking, and to ease cleaning.
Comine marinara or spaghetti sauce & pasta in a large bowl. Stir until all the pasta is covered.
In another bowl combine 2 cups shredded mozzarella with 1/2 cups of the grated Parmesan.
Pour approximately a third of the penne that has been sauced into the bottom of the slow cooker and form a thin layer. Evenly sprinkle half the mixture of mozzarella-parmesan on the pasta.
Sprinkle the remaining mozzarella-parmesan evenly over the layer of penne that is already covered with the sauce and then add another third of the same to the cheese layer. Add the remaining one-third of the sauced penne, and pat the top with the back of a spoon.
In a small bowl, add the rest of the shredded mozzarella, 1 cup and the rest of the grated parmesan, 1/2 cup. Pour this mixture thoroughly over the top of the pasta in order to form a blanket of cheese which will become golden and bubbly.
Cook in the slow cooker covered with its lid on low and after 2 1/2 to 3 1/2 hours, the pasta is tender and not mushy. Avoid opening the lid within the first 2 hours to keep heat in.
At about 2 1/2 hours, remove the lid and test a pasta piece in the middle to check doneness. If it is still firm, cover again and continue cooking every 20 to 30 minutes until tender and cheese is melted and bubbling.
To serve, use a large spoon or spatula to scoop out the hot mostaccioli in large heaps with layers, making sure each dish has lots of cheese and sauce. Pasta should be saucy, not soupy, and cheese should be stretchy.