Preheat the oven to 350 degrees. Line a baking sheet with a silpat mat.
Combine together the flour, baking soda, baking powder, and salt in a small bowl; mix well.
In a large bowl, cream together the butter and peanut butter with a hand mixer, until combined. Add 1/2 cup of the white sugar and the brown sugar then beat until creamy and smooth. Add the egg and vanilla. Mix until combined.
Slowly add in the dry ingredients and mix with a spoon, until just combined.
Take about 2 tablespoons of dough and form into a ball.
Roll in the remaining 3 tablespoons of white sugar.
Place the cookies on the prepared baking sheet, about 2 inches apart.
Place into the oven and bake the cookies for 9-10 minutes or until they are golden at the edges and just set. Don’t over bake!
Remove from the oven and let the cookies set on the baking sheet for 5 minutes before transferring to a cooling rack.
Once the cookies are cool and hardened, melt the dark chocolate, with 1/2 teaspoon of coconut oil, according to package directions.
Dip half of each cookie into the melted dark chocolate, tapping off the excess, and place on a piece of parchment paper.
Sprinkle each cookie immediately with sprinkles (so it will stick before the chocolate hardens).
Store in a sealed container with parchment paper between layers.
Serve with ice cold milk. Enjoy!