Prep: Heat oven to 350°F (175°C). Grease a 9×5-inch loaf pan.
Mix: In a large bowl combine ground beef, onion, milk, bread crumbs, and egg; season with salt and pepper. Mix gently until just combined. Press mixture into the pan.
Glaze: Stir together ketchup, brown sugar, and mustard; spread evenly over the loaf.
Bake: Bake 55–65 minutes, until an instant-read thermometer registers 160°F (71°C). Rest 10 minutes, then slice.
Why This Recipe Works
Panade effect: Milk and crumbs keep the loaf juicy and tender.
Sweet-tangy glaze: Ketchup, brown sugar, and mustard caramelize into a shiny cap.
Gentle mixing: Prevents a dense texture—handle lightly for the best crumb.
Expert Tips & Variations
Sauté the chopped onion in a little butter until translucent for milder sweetness.
Add 1 tablespoon Worcestershire sauce and 2 tablespoons chopped parsley to the meat mixture for depth.
Swap bread crumbs for crushed saltines or panko; use half beef, half pork for richer flavor.
Meal prep: cool leftovers completely, then slice and refrigerate up to 4 days or freeze up to 2 months.