Step 1

Preheat oven to 350°. Line a muffin tin with 12 liners.

Step 2

In a large bowl, whisk together flour, cocoa powder, pumpkin pie spice, baking soda, baking powder, and salt.

Step 3

In another large bowl, combine melted butter, sugar, sour cream, vanilla, egg and egg yolk until smooth. Fold in pumpkin puree.

Step 4

Combine wet and dry ingredients. Fold in chocolate chips.

Step 5

Scoop batter into muffin liners. Bake for 15 minutes.

Step 6

Sprinkle a few extra chocolate chips onto each muffin as they get out of the oven. Press lightly into each muffin.

Step 7

Let cool 5 minutes before transferring muffins to a cooling rack.