Marvel at the hypnotic vanilla and cocoa swirl of this light loaf cake’s marbled centre. With an added touch of sweetness from the glaze, you’ll be cutting a slice for afternoon tea, an after-dinner snack, and perhaps even a cheeky breakfast.  For best results, beat the butter and sugar really well, ensuring they are light and fluffy and the sugar is dissolved. When alternating adding flour and milk, always start with a bit of flour. Timings Prep time: 25 minutes Cook time: 1 hour Serves 8 Ingredients For the cake 200g unsalted butter, softened, plus extra for greasing 350g caster sugar 1 tsp vanilla extract 4 medium eggs, at room temperature 195g plain flour 1 tsp baking powder 90ml whole milk 25g Dutch-processed cocoa powder For the glaze 30g unsalted butter 60g caster sugar ½ tsp vanilla extract Method To make the marble cake, preheat the oven to 180C/160C fan/gas mark 4. Grease a 21 x 11cm loaf tin and line the base with baking paper. You can also use an 18-20cm round or square tin. In a …