Split 4 hot cross buns, reserving a little butter, use 60g to butter the buns, sandwich together and cut into quarters.
Butter a shallow ovenproof dish and arrange the buns.
Beat together 2 eggs, 500ml milk and the finely grated zest 1 orange and pour over the buns.
Soak for at least 30 mins. Sprinkle ½ tsp mixed spice and 2 tbsp demerara sugar over the top and bake in a preheated oven at 170C for around 25 mins or until set.