Prepare two cookie sheet pans by lining with parchment paper or a silicone baking mats.
Preheat oven to 375 ℉
Combine flour, baking powder and baking soda in a bowl. Set aside.
Place softened butter, granulated sugar, brown sugar and peanut butter in the bowl of a stand mixer (note: a hand mixer may also be used). Mix on medium speed until light and fluffy (approximately 3 - 4 minutes). Scrape sides of bowl as needed.
Add egg and mix until well combined. Scrape sides of bowl as needed.
Add the dry ingredients (flour, baking powder, baking soda) and mix until just combined. Scrape sides of bowl as needed.
Scoop out two tablespoons of cookie dough. Roll in granulated sugar and place on baking sheets. Leave approximately 2" of space between each cookie.
Bake 8 - 10 minutes (edges will be a light brown color). Remove from oven and let cool for 10 minutes on baking sheets. Move to a wire rack to cool completely.
Decorate cookies
Place chocolate chips in a microwave safe bowl. Heat on 50% powder in 20 second bursts, stirring between each heating. Alternatively, place bowl over a pot of simmering water and heat until the chips melt, stirring often. Transfer melted chocolate to a piping bag.
To make spider legs, pipe 4 lines diagonally across each cookie intersecting at the center of the cookie. Place mini peanut butter cup in the middle of each cookie. Pipe two small dabs of chocolate on each peanut butter cup and place a googly eye on each dab. Allow melted chocolate to set.