1.
Preheat toaster oven to 350 degrees F and line a baking pan with foil.
2.
Lightly toss beef, sausage, egg, onion, milk, and breadcrumbs together in a mixing bowl. Salt and pepper, form into a flat (3-inch) loaf, and place on baking pan.
3.
Whisk together the brown sugar, mustard, and ketchup in a small bowl. Brush over the meatloaf.
4.
Bake for 45 minutes to an hour, until meat is cooked through.