Add onion to pan; cook 6 minutes or until tender, stirring occasionally.
Remove from heat; cool slightly.
Combine onion, 3 tablespoons ketchup, and remaining ingredients in a bowl, and gently stir just until combined.
Place meat mixture on a baking sheet coated with cooking spray; shape into an 8 x 4-inch loaf. #Brush top of loaf with remaining 3 tablespoons ketchup.
Bake 35 minutes or until meat thermometer registers 70°C/160°F at the centre.