Prep: Preheat your oven to 350°F. Lightly spray a standard loaf pan with non-stick cooking spray.
Mix: In a large bowl, combine the ground meat, saltines/breadcrumbs, egg, garlic, onion, Worcestershire sauce, and ketchup. Pro Tip: Use your hands to mix until just combined; over-mixing can lead to a dense, tough meatloaf.
The First Layer: Divide the meat mixture in half. Press the first half firmly into the bottom of the prepared loaf pan.
Stuff: Layer the Swiss cheese slices over the meat, then sprinkle the shredded Colby and Monterey Jack on top. Keep the cheese slightly away from the absolute edge of the pan.
Seal: Place the second half of the meat mixture over the cheese. Use your fingers to go around the entire perimeter, pinching the top and bottom meat layers together to create a tight seal.
Glaze & Bake: Spread a generous layer of ketchup (or BBQ sauce) over the top. Bake for 60 minutes or until the internal temperature reaches 160°F for beef/sausage or 165°F for turkey.
Rest: Let the meatloaf rest in the pan for 10 minutes before slicing. This prevents the cheese from running out too quickly and keeps the meat juicy.