1: Remove the crusts from 4 slices sandwich bread, cut each slice in half to give, ideally, pieces the same height as your mould.
2: Butter the bread slices on both sides and fry until golden brown.
3: Use a brush to coat the inside of your charlotte mould with melted butter.
4: Put 2 tablespoonsful of caster sugar into the buttered mould and shake until the sugar is evenly distributed and stuck to the butter all over.
5: Line the base and sides of the mould with the slices of fried bread, cutting to size where necessary and filling any holes with the trimmings until completely covered (yes, I know, it looks a bit like a jigsaw puzzle or bread Tetris).