Preheat oven to 350°F and lightly grease an 8x8-inch baking dish.

In a large bowl, combine beaten eggs, milk, and crushed crackers. Stir in onion and shredded cheese.

Add ground beef, salt, and pepper. Mix until just combined and shape into a loaf in the prepared dish.

Bake for 30 minutes. Meanwhile, mix ketchup, brown sugar, and mustard to make the glaze.

Spread half of the glaze over the meatloaf and return to oven for 10 minutes.

Spread remaining glaze on top and bake an additional 5–10 minutes, until fully cooked through.

Let rest a few minutes before slicing and serving.