Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter with peanut butter and both sugars until fluffy.
Add in the egg and vanilla extract, and mix until smooth. Fold in the sprinkles. Roll the cookie dough into balls and flatten slightly. Place one Reese's peanut butter cup in each cookie and roll into a ball.
Place onto a large ungreased baking sheet at least 2-inches apart. Bake for 10-12 minutes.