Preheat the oven to 350 F. Line 2 baking sheets with parchment paper or silicone baking mats.
Microwave the butter in a large, microwave-safe bowl for about 40 seconds. Butter should mostly melted.
½ cup butter
Whisk the butter until it is completely melted.
Add the sugars; mix until well-combined.
¾ cup brown sugar, ¼ cup granulated sugar
Stir in vanilla and egg until incorporated.
1 teaspoon vanilla extract, 1 large egg
Add the flour, cocoa powder, baking soda, and salt. Please read the recipe note about properly measuring flour.
1 ⅓ cups all-purpose flour¹, ⅓ cup unsweetened cocoa powder2, ½ teaspoon baking soda, ¼ teaspoon salt
Mix dough until just combined. Dough should be soft and a little sticky but not overly sticky.
Stir in chocolate chips.
¼ cup mini semisweet chocolate chips
Scoop out 1.5 tablespoons of dough (medium cookie scoop).
Dip the top of the cookie dough into the sprinkles.
Halloween sprinkles
Gently press 2 candy eyes into the top of the dough.
48 small candy eyes
Place dough 2 inches apart on baking sheet.
Bake for 7-10 minutes, or until cookies are set. They will be puffy and still look a little underbaked in the middle.3
Notes
Flour: Be sure to fluff and then scoop and sweep to measure the flour. Too much flour will result in a dry or crumbly cookie.
Cocoa powder: I use regular unsweetened cocoa powder, not Dutch-processed.
Candy eyes: I bought a package with small, medium, and large candy eyes. I used the smallest sized eyes for these cookies.
Sprinkles: Just dip the tops into the sprinkles but don't roll the entire cookie in sprinkles. Sprinkles on the bottom of the cookie can melt as the cookies bake.
Don't over-bake the cookies, or you won't end up with soft cookies. Since oven temps can vary, I suggest starting with the listed baking time and increasing the time as needed.