Warm the custard in a pan. When its steaming, remove from the heat and add the chocolate, stirring until melted. Transfer to a piping bag and cool to room temperature, then chill until you’re ready to fill the doughnuts.

Heat the oven to 180C/160C fan/gas 4. Separate the hot cross buns and warm in the oven for 3-5 mins. Meanwhile, melt the butter and pour into a bowl. Combine the sugar and cinnamon in a second bowl.

Brush each warm bun in melted butter, then roll them in the cinnamon sugar. Poke a hole in the side of each bun with a skewer or small, sharp knife, inserting it to the centre of the bun but being careful not to break through the sides.

Snip off the end of the piping bag, insert it into each bun and gently squeeze to fill them with chocolate custard.