01 -
Preheat oven to 350°F (175°C) and line a 12-cup muffin tin with liners or coat with nonstick spray.
02 -
In a large bowl, whisk together pumpkin puree, melted butter, sugar, egg, and vanilla until smooth and well combined.
03 -
In a separate bowl, whisk together flour, baking soda, baking powder, salt, and cinnamon.
04 -
Gently fold dry ingredients into wet mixture until just combined, being careful not to overmix.
05 -
In a small bowl, stir together melted butter, brown sugar, and cinnamon until smooth.
06 -
Fill each muffin cup halfway with batter, add a spoonful of cinnamon swirl mixture, then top with remaining batter.
07 -
Use a toothpick to lightly swirl the cinnamon mixture through the batter with just a few strokes.
08 -
Bake for 20-25 minutes, until a toothpick inserted in center comes out clean and tops are golden brown.
09 -
While muffins are cooling, whisk together powdered sugar, vanilla extract, and milk until smooth, adjusting consistency as needed.
10 -
Drizzle glaze over slightly cooled muffins before serving.