Preheat the oven to 200 C, Gas Mark 6. Line 6-8 Muffin moulds with muffin cups or 10 cm by 10 cm squares of greaseproof paper.
Sift the flour and baking powder together in a bowl, then stir in the sugar.
In another bowl whisk together the eggs, coffee, milk and oil. Pour the liquid ingredients into the flour mixture. Add the blueberries and stir until just combined.
Spoon the mixture into the cases and bake in the oven for 25 minutes or until golden and cooked through. Test by inserting a knife to see if it comes out clean.
Leave to cool in the tin for 5 minutes before turning out on to a wire rack to cool completely. Serve in their cases.