Quick cheese sage and onion bread

This quick bread is from Delia Smith’s Christmas, and a firm family favourite. The sage makes it Christmassy I guess! Serves 6-8.

350 gms onions finely chopped
2 tablespoons olive oil
350 gms self raising flour
2 teaspoons salt
2 teaspoons mustard powder
24 fresh sage leaves, snipped across into thin strips
110 gms strong Cheddar cheese, grated
1 egg
Approximately 5 tablespoons milk

Brown the onions in the oil over a medium heat for about 10 mins, remove from the pan and leave to cool.
Mix the on...