Step 1
Preheat the oven to 190°C (375°F). Grease 12 muffin cups or line with paper muffin liners.
Step 2
In a bowl, sift together the flour, sugar, baking soda, baking powder, salt, and nutmeg. In a separate bowl, whisk together the melted butter, egg, buttermilk, and vanilla.
Step 3
Pour the buttermilk mixture into the dry ingredients and stir just until mixed (the batter will not be smooth). Gently stir in fruit, if desired.
Step 4
Scoop the batter into the prepared muffin tins, filling the cups almost to the top. Bake in the preheated oven until golden and the tops spring back when lightly pressed, about 18 minutes.