Line a 12-hole, 80ml muffin pan with paper cases. Preheat oven to 180°C.
In a large bowl, combine the flour, sugar, pumpkin, cinnamon and blueberries. In a jug, whisk together the egg, oil and buttermilk. Add the egg mixture to the pumpkin mixture and stir until just combined. Be careful not to overmix.
Divide mixture among the paper cases. Top with leftover blueberries and museli. Bake for 25-30 mins or until a skewer comes out clean. Serve warm or freeze for meal prep.