Put the 100g of butter and sugar in a mixing bowl. Use a wooden spoon to cream until it's pale and fluffy.
Beat the eggs together with a fork and then gradually beat into the creamed mixture, along with the vanilla extract.
Mix the peel with the flour in a bowl and use a metal spoon to gently fold the flour and peel into the creamed mixture.
Use the remaining butter to liberally grease the pudding basin with the butter wrapper or a pastry brush.
Cut out a circle of parchment paper to line the base and grease this as well.
Cut the cherries in half and arrange a few halves, cut side down on the base of the basin.
Carefully add some of the sponge mixture to just cover the cherries and keep them in place.
Add a few halves around the bottom sides and add more mixture.
Repeat until the cherries and sponge mixture are used up.
Cut out a large circle of parchment to cover the top and halfway down the sides.
Make a pleat in the middle of the circle and use string to tie it around the top of the basin securely.
Place the pudding in a saucepan and pour boiling water to come halfway up the sides of the basin.
Put the lid on the pan and simmer for one and a half hours. Keep an eye on the water level and top up if required.
Carefully remove the basin from the water and leave the pudding to rest for a few minutes.
Remove the baking parchment and run a knife around the edge of the basin.
Turn out onto a plate to serve.