Line 16 muffin cups with liners.
In a large bowl combine the butter, sugar, brown sugar, eggs, pumpkin, milk, and vanilla. Whisk until the sugar has dissolved, about 2 minutes.
Set a fine mesh strainer over the bowl and add the flour, cocoa powder, baking powder, baking soda, and salt. Sift the dry ingredients on top of the wet ingredients, then use a rubber spatula to fold them together until no bits of dry flour remain. Fold in the chocolate chips.
Use a spring-loaded cookie scoop to divide the batter between the prepared muffin tin (or tins). Bake until a cake tester inserted in the middle of a muffin comes out clean, 25 to 30 minutes. Let cool on a wire rack for about 20 minutes before enjoying. Leftover muffins will keep at room temperature in a tightly-sealed container for up to 4 days. Love the recipe? Leave us stars and a comment below!
