Preheat the oven to 180°C/Gas 4. Lightly grease the mini muffin tin.
Sift the flour into a bowl then rub in the butter until the mixture resembles breadcrumbs. Stir in the cinnamon then add the blueberries and mashed banana.
In a separate small bowl, lightly whisk the egg and yogurt together and then pour the mixture into the dry ingredients, stirring gently with a spatula until combined
Spoon the mixture equally into the prepared muffin tin, sprinkle with pumpkin seeds and bake for 20-22 minutes or until well risen and golden. When the muffins have cooled slightly, remove from the tin and cool on a wire rack. Store in an airtight container for up to 3 days, or freeze for up to a month.
Tips: Try different toppings such as poppy or sunflower seeds. This recipe can also be made with standard self-raising flour if you prefer.