The muffin base was quite simple:
100g caster sugar
1 egg (although I only had 2 small bantam eggs to hand)
50g melted and cooled butter
1 tsp baking powder
175g self-raising flour
Cream together the sugar and egg, mix in the flour and baking powder gently, and add the melted butter, followed by the milk. The mixture looked a bit of a mess at this point - but I had faith. To the mixture, I added the grated rind of one lemon and one orange, plus a few chunks of orange, chopped up into small chunks.
Bake at 180 degrees (fan oven) for about 25 minutes.
Once cooled, I creamed together butter and icing sugar, with a splash of milk, together with more lemon rind, orange rind, and a splash each of lemon and orange juice. I like to make the buttercream quite tart, so I add more lemon than orange.
The muffins are light and fluffy, but still with that chunkiness of a muffin, with added luxury of the buttercream. Happy Mother's Day!
I have to add, those paper cases were a sod. They'd expanded in the drawer, so I had to re-fold every single one of the creases on every single blummin case.... it took forever. I won't be buying that brand of paper case again!