Lasagna-style Baked Ziti... Lasagna-style Baked Ziti   Ingredients 12 ounces ziti (about 4 cups) 1 tablespoon olive oil 1 large onion, chopped 2 cloves garlic, finely chopped 1/2 pound lean ground beef kosher salt and black pepper 1 26-ounce jar marinara sauce 1 bunch spinach, thick stems removed (about 4 cups) 1/2 cup ricotta 1/2