- Before getting started, preheat your oven to 350°F (175°C).  
- Then, in a large mixing bowl, beat together the softened butter, granulated sugar, peanut butter, and brown sugar until the mixture becomes light and fluffy. 
- Stir in the egg and vanilla extract until evenly mixed. 
- In another mixing bowl, blend together the flour, baking powder, baking soda, and salt by whisking thoroughly. 
- Pour the dry ingredients into the wet mixture little by little, and stir gently until they're fully incorporated. 
- Using your hands, create 1-inch-sized balls from the dough and position them on a baking sheet lined with parchment paper, maintaining a distance of about 2 inches between every cookie. 
- Press lightly with a fork on each cookie to make a crosswise design. 
- Wait for the edges to become slightly golden, a process that takes between 10-12 minutes, and let the cookies rest for 5 minutes on the baking sheet before transferring them to a wire rack to cool down entirely.