Combine the butter, sugar, brown sugar, peanut butter and egg in the bowl of an electric mixer and set to low-medium speed.
Once combined, slowly add in the baking soda, baking powder, and flour.
Wrap the dough in plastic and refrigerate for 1-2 hours.
Once the dough is chilled, preheat your oven to 375°F.
Roll the dough into 1-inch balls and place on the cookie sheet about 2-inches apart. Use a fork to make a crisscross shape onto the top if each cookie.
Bake the cookies for 10-12 minutes, or until light brown around the edges.
Remove from the baking sheets to a cooling rack and let cool completely.
After the cookies are completely cool, melt the dark chocolate in a microwave-safe bowl for 1 and 1/2 minutes on 50% power then stir. If more time is needed place the bowl back in the microwave for 15 seconds, then stir again.
Dip each cookie 1/3 of the way into the melted dark chocolate, letting any excess drip off before placing it back onto the cooling rack or onto a sheet of wax paper.
Immediately sprinkle on a pinch of chopped peanuts, then allow the chocolate to set before serving.