Line 8 sections of a 12-section muffin tray with paper muffin cases. Sift the flour and baking powder into a bowl and stir in the sugar.
Beat together the egg, maple syrup, milk and melted butter in a separate bowl and then mix into the dry ingredients until only just combined. Fold in the chocolate and pecan nuts.
Divide the muffin mixture between the paper cases and top with some extra chopped nuts and chocolate.
Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 20–25 minutes or until risen and golden. Transfer to a wire rack to cool.