Zest the orange and juice one ... line them with paper, or butter the insides before adding the batter. Finally, spoon some of the crumble over each muffin, and pop them in the oven.

Cool and then chill. Set oven to 180oc and line a tray with parchment paper. Rub the butter into the flour to coarse crumbs. Rub in the sugar and then mix in the orange zest. Spread onto the tray ...