1. Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius).
2. Flatten out the chicken pieces. Mix the oil, soy sauce, and garlic in a bowl and brush onto the chicken.
3. Take each chicken breast and fold the uneven side underneath it. Place into a nine- x 13-inch (23- x 33-centimeter) pan or small baking sheet, fitting the folded chicken pieces neatly into the pan. The chicken will take the shape it’s baked in, so try to form each piece into a square. By placing them close together, they won’t be able to unfold.
4. Cover the pan and bake for one hour. (You can freeze them at this point.) Uncover and bake for another 20 minutes or so.