Preheat oven to 180C/350F. Oil or spray a loaf tin.
Glaze: Mix together in a small bowl. Set aside.
Meatloaf: Place breadcrumbs in a very large bowl. Grate over onion. Mix so the breadcrumbs are all wet.
Add remaining ingredients. Mix well using your hands. Form into a loaf shape, pinching together then smoothing over creases and cracks.
Transfer into loaf tin. Brush generously with glaze, using about ½.
Bake for 45 minutes. Remove from oven and brush with most of the remaining glaze. If there is excess fat pooling, scoop/pour it off.
Bake for a further 30 minutes. Remove from oven.
Stand for 10 minutes before turning out and cutting into thick slices.
