Preheat oven to 375F and line a baking sheet with parchment paper.
In a large mixing bowl, whisk together the flour, salt, and baking soda until evenly combined.
In a second bowl with an electric mixer, cream together on medium high speed the sugars and butter until light and fluffy for about 2 minutes. Scrape down the bowl as needed.
Beat in egg to mixture until evenly combined.
Mix in peanut butter and vanilla until smooth and creamy.
Beat in the flour mixture until just combined. Do not overmix.
Using a small cookie scoop, or two spoons, scoop the dough (about 2 tablespoons) and roll dough into 1 inch balls and then roll in granulated sugar. Place on baking sheet and flatten with fork slightly.
Bake in center of the oven for 10-12 minutes until edges are set and middles are still soft. Remove form the oven and cool on the baking sheet for 5 minutes. Transfer to a wire rack.
After they are completely cooled, melt the white chocolate chips in the microwave in 30-second intervals, stirring in between each interval. I like to add a a tablespoon of shortening to help smooth out the chocolate and make for a silky finish. Dip each cookie halfway in the chocolate and set on parchment paper. Cover with sprinkles before the chocolate sets.