Line a 12-section bun tray with paper cake cases. Put the butter, the 125 g (4 oz) sugar, eggs, flour and baking powder in a bowl and beat with a hand-held electric whisk for about a minute until light and creamy.
Spoon half the cake mixture into a separate bowl. Blend the coffee powder with the boiling water and stir into half the mixture. Using a teaspoon, fill the paper cases with the 2 mixtures, then draw a knife in a circular motion through each cupcake to mix the mixtures partially together to create a marbled effect.
Scatter the flaked almonds over the cakes. Mix the remaining 2 teaspoons sugar with the cinnamon and sprinkle over the cakes.
Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 20 minutes or until risen and just firm to the touch. Transfer to a wire rack to cool.