Preheat oven to 350°F and line a 12-count muffin tin with paper liners. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and brown sugar on medium speed until well combined, about 2 minutes.
½ cup unsalted butter, ½ cup brown sugar
Add the eggs and vanilla. Mix until just combined, scraping down the sides of the bowl as needed.
2 large eggs, 1 teaspoon pure vanilla extract
Add the molasses and mix until combined.
½ cup unsulphured molasses
In a large bowl, whisk together the flour, baking soda, cinnamon, ginger, nutmeg, and cloves.
2½ cups all-purpose flour, 1 teaspoon baking soda, 1 teaspoon ground cinnamon, 1 teaspoon ground ginger, ½ teaspoon ground nutmeg, ¼ teaspoon ground cloves
With the mixer on low speed, alternate between adding the dry ingredients and the milk in batches - ⅓ flour, ½ milk, ⅓ flour, last ½ milk, last ⅓ flour. Mix just until combined.
½ cup milk
Divide the batter between the muffin pans, filling each one ¾ of the way full. Top with a sprinkle of coarse sugar, if desired.
Coarse sugar
Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
Transfer the muffins to a wire rack and let cool before serving.