In a large mixing bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking soda, and ½ teaspoon of salt.

In another bowl, cream together ½ cup of unsalted butter, ½ cup of light brown sugar, ½ cup of granulated sugar, and 1 cup of smooth peanut butter until light and fluffy.

Add 1 egg, 1 teaspoon of vanilla extract, and ¼ cup of whole milk, then mix until fully combined.

Gradually add the dry ingredients to the wet mixture, stirring until a soft dough forms.

Transfer the peanut butter cookie dough into an airtight container or wrap it in plastic wrap. Chill in the refrigerator for at least 30 minutes.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Once the dough is chilled, scoop tablespoon-sized portions onto the prepared baking sheet, spacing them about 2 inches apart.

Bake for 10-12 minutes, or until the edges are lightly golden but the centers look slightly underbaked. Let them cool for about 3-5 minutes before transferring to a wire rack.

Press a Miniature Reese's Peanut Butter Cup into the center of each cookie to create the spider's body.

Melt ½ cup of semi-sweet chocolate in a microwave-safe bowl in 30-second intervals, stirring between each until smooth.

Using a piping bag, pipe chocolate legs extending from the Reese's and place two candy eyes on top.

Chill the decorated cookies in the refrigerator for about 10-15 minutes to ensure the chocolate hardens.