Step 1

In a medium bowl, add flour, cocoa powder, baking soda, and salt and whisk to combine. Set aside.

Step 2

In the bowl of a stand mixer (or in a large bowl using a handheld electric mixer), cream the butter and both sugars until light and fluffy.

Step 3

Add egg, milk, and vanilla to the butter mixture and beat to combine.

Step 4

With the mixer running on low speed, slowly add the flour mixture to the butter mixture blending until combined and stopping to scrape the bowl as needed.

Step 5

Cover the bowl with plastic wrap and place the cookie dough in the fridge to chill for 30 minutes.

Step 6

Preheat the oven to 350°F (177°C). Line cookie sheets with parchment paper and set aside.

Step 7

Use a 1 ½ Tablespoon cookie scoop or measuring spoons to scoop 1 ½ Tablespoon balls of cookie dough. Placing each cookie dough ball onto the prepared baking sheets at least 2 inches apart.

Step 8

Bake the cookies, one tray at a time, for 10 minutes or until the cookies are flattened with slightly puffed centers. Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.

Step 9

When the cookies are completely cooled, melt the white chocolate wafers in a small bowl in the microwave on 50% power in 30 second increments, stirring until completely melted and smooth.

Step 10

Add the melted chocolate to a piping bag fitted with a small round piping tip (or simply use a large plastic food storage bag with one corner snipped off). Working quickly (since the chocolate will firm up as it cools), decorate the cookies.

Step 11

To decorate mummy cookies, pipe a small drop of melted chocolate onto the back of two candy eyeballs. Affix the eyeballs just above the center of a cookie. Pipe lines of chocolate back and forth, covering each corner of the cookie, to create the mummy's wrapping.

Step 12

To decorate spiderweb cookies, pipe a spiral of melted white chocolate onto a cookie. Using a toothpick, drag lines from the center of the cookie outward to create the spiderweb pattern.