Place butter, peanut butter, 1/2 cup granulated sugar, brown sugar, the egg, and vanilla extract into a large bowl.
Use a medium cookie scoop to scoop the dough into a ball (you'll make about 26 cookies) and drop the cookie dough ball into the bowl of sugar.
Gently roll it around in the sugar until the dough is fully coated.
*Some people have trouble with cookies spreading, so I’d suggest doing a test batch of 1 or 2 cookies to see if they spread. If they DO, cover the cookie dough bowl (Step 6, before you scoop any more cookies) in saran wrap and place in fridge for at least an hour. See my notes in the post above for making the dough ahead of time.
** See my notes above on storing and or freezing these cookies.