Preheat the Oven: Preheat your oven to 350°F (175°C). Line a muffin tin with paper liners or grease it lightly with cooking spray.
Mix Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, ground ginger, ground cinnamon, ground nutmeg, and salt. Set aside.
Cream Butter and Sugars: In a large mixing bowl, use an electric mixer to cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes.
Add Egg and Molasses: Beat in the egg until well combined, then stir in the molasses, buttermilk, and vanilla extract until smooth.
Combine Wet and Dry Ingredients: Gradually add the dry ingredients to the wet mixture, mixing just until combined. Be careful not to overmix; a few lumps are okay.
Fill Muffin Tin: Divide the batter evenly among the prepared muffin cups, filling each about 2/3 full.
Bake: Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Cool and Serve: Allow the muffins to cool in the tin for about 5 minutes, then transfer them to a wire rack to cool completely. Enjoy them warm or at room temperature.