In a large mixing bowl, cream together softened unsalted butter(½ cup, i.e., 1 stick), light brown sugar (¾ cup), granulated sugar(¼ cup), and peanut butter(½ cup) with an electric mixer for 30 seconds. Add egg(1 large) and stir until combined.
On low speed, add in vanilla extract (1 teaspoon) and salt(¼ teaspoon). Add baking soda(½ teaspoon) and stir for 10 seconds. Slowly add in all-purpose flour (1 ½ cups) and mix for 30 seconds, or until the dough is combined.
Scoop and roll into 2-tablespoon sized balls and place on a parchment-covered baking sheet. Lightly flatten the tops of each cookie so they are more like thick discs. This will help them bake more evenly.
Bake at 350℉ for 8-10 minutes.
Immediately after removing from the oven, press a Reeses pumpkin into the center of each one. Once the chocolate starts to melt (3-5 minutes), press two candy eyeballs and a half of a white chocolate chip to create the mouth. Allow for the cookies to continue to cool on baking sheet for 5-10 minutes until removing cookies from the baking sheet. To harden chocolate, place in refrigerator for 15-30 minutes.