Food Network teaches how to crush, slice and mince garlic. Peel off some of the papery skin from the garlic and then smash the head of garlic with the heel of your hand to loosen the cloves; if you only need a few cloves, leave the head intact and pull some off. Separate the cloves. To peel a clove, cut away the root end with your knife. Lay the flat side of the knife over the clove while holding the knife handle, then with the heel of your free hand carefully whack the knife against the garlic to separate the skin from the clove. To crush the peeled garlic, lay the flat side of the knife over the clove and smash it again. To slice peeled garlic, lay the clove flat on the cutting board and hold it with the fingertips of one hand, keeping them curled under. Using a rocking motion with the knife, make thin slices by moving the knife slowly across the clove. To mince peeled garlic, lay the flat side of a knife over the clove and smash it. Roughly chop the clove then move your free hand flat across the tip of the knife and use a rocking motion to chop the garlic until it’s finely minced.
Bring a medium pot of salted water to a boil over high heat. Add the pasta and cook until just tender, stirring occasionally, about 5 minutes. Drain pasta into a large mixing bowl.
Meanwhile, put the olive oil in a medium saute pan over medium heat. Add the chicken and cook for 3 minutes. Add the onions and garlic, stirring to combine, and cook until the onions are soft and the chicken is cooked through, about 5 minutes more. Put the chicken mixture into the bowl with the cooked pasta. Add the canned tomatoes, mozzarella cheese, parsley, salt, and pepper. Stir to combine. Place the mixture in a buttered 8 by 8 by 2-inch baking dish. In a small bowl mix together the bread crumbs and the Parmesan cheese. Sprinkle over the top of the pasta mixture. Dot the top with small bits of butter. Bake until the top is golden brown, about 30 minutes.