A reader asks how she could bake one of my cake recipes in a different size tin from that I’d specified. I replied by explaining how to work out the capacity of a round, square or oblong cake tin mathematically so that the mixture would still turn out well.
But then I realised that there is a far simpler way to discover the capacity of a cake tin.
I wanted to make the double-layer January Lemon Cake in my book, CAKES, as a single-layer cake to decorate with fresh primroses and miniature chocolate eggs for Easter. So I filled one of the two sponge-cake tins recommended in the original recipe with water and poured it into the larger, deeper cake tin I planned to use; then repeated the water trick. Success – no water spilled out of the larger cake tin showing it would hold the same amount of raw cake mixture perfectly well.
If you wish to use the water test for a spring-form cake time with a detachable base, it’s sensible to place a strong plastic bag in the tin before pouring in the water.
EASTER PRIMROSE CAKE
175g / 6 oz unsalted butter – at room temperature
175g / 6 oz caster sugar
1 small lemon
175g/ 6 oz self-raising flour
90g/ 3 oz unsalted butter
1 small lemon
230g/ 8 oz icing sugar, sifted
about 20 fresh primroses
about 30 miniature Easter eggs
Preheat the oven to 180’C/ fan 160’C/ 350’F/gas mark 4.
Lightly butter the inside of a 20cm/8in diameter non-stick cake tin and line the base with baking paper.
Beat the butter with the caster sugar and the finely grated zest of the lemon until light and fluffy. Mix in the eggs, one at a time, until well combined. Fold in the sifted flour with the strained juice of half the lemon.
Spoon the mixture into the prepared cake tin and smooth level.
Bake in the preheated oven 30-35 minutes until the cake is golden-brown and just starting to shrink from the sides of the tin. Remove the cake from the oven and leave to cool slightly in the cake tin for 3 minutes then turn out onto a wire rack and leave until cold.
To make the frosting: squeeze the juice from both the reserved half of lemon plus the whole lemon. In a small glass or stainless steel saucepan melt the butter with 3 tablespoons of strained lemon juice. Bring to the boil and allow to bubble for 30 seconds then remove from the heat and cool for one minute. Stir in the icing sugar and beat until smooth. Stand the pan in cold water to cool and slightly thicken the frosting. Pour the frosting over the cake allowing it to run down the sides.
Leave the cake until the frosting has set, transfer to a flat serving plate or board and decorate with the primroses – both the flowers and leaves are edible – and the Easter eggs.