Heat the oven to 180 C and line a 12 hole muffin tin with cupcake or muffin cases. Mix the flour, sugar, almond flour, lemon zest and poppy seeds together in a large mixing bowl. Beat the eggs into the yogurt, then tip this into the dry ingredients with the melted butter. Mix together with a wooden spoon or whisk until lump-free, then divide between the cases. Bake for 20-22 minutes until a skewer poked in comes out clean - the cakes will still be quite pale on top. Cool for 5 minutes in the tin, then carefully lift onto a wire rack for finish cooling
To ice, beat the softened butter until really soft in a large bowl, then gradually beat in the icing sugar and lemon juice. Stir in enough food colouring for a pale yellow color. Then spoon the icing into a piping bag with a large star nozzle.
Pipe the cakes and sprinkle with sprinkles of your choice