Pumpkin Doughnut Muffins

10 Tbsp butter, room temperature
3 c all-pupose flour
2-1/2 tsp baking powder
1/4 tsp baking soda
1 tsp salt
1/2 tsp nutmeg
1/4 tsp allspice
1/3 c buttermilk
1-1/4 c pure pumpkin puree
3/4 c light brown sugar
2 large eggs
 
sugar coating:
3/4 c granulated sugar
1-1/2 tsp cinnamon
1/4 c butter, melted
 
Preheat oven to 350°F. Butter and flour 12 standard muffin cups. Make batter: In medium bowl, whisk together flour, baking powder, baking soda, salt, nutmeg, and allspice. In a small bowl, whisk together buttermilk and pumkin puree. In a large mixing bowl, using an electric mixer, beat butter and brown sugar until light and fluffy. Beat in eggs, one at a time, scraping down bowl as needed. Wirh mixer on low, add flour mixture in three additions, alternating with two additions pumpkin mixture; and beat to combine.
 
Spoon 1/3 cup batter into each muffin cup and bake until a toothpick inserted into center of muffin comes out clean, about 30 minutes. Meanwhile, in a medium bowl, combine granulated sugar and cinnamon. Let muffins cool 10 minutes in pan on wire rack. Working with one at a time, remove muffins from pan, brush all over with melted butter, then toss to coat in sugar mixture. Let muffins cool completely on a wire rack.