Beat butter with sugars for about 2- 3 minutes. Add peanut butter and mix 1-2 more minutes. Mix in eggs and vanilla and beat for another 2-3 minutes. Add the flour and baking powder and mix until well combined. Stir in half of the peanuts.
Use a cookie scoop to scoop out cookies onto parchment or silicone-mat lined cookie sheets. Lightly press the rest of the nuts on top of the cookies.
Bake for about 14 minutes. The very edges should be a light golden brown, but cookies should still be really soft in the middles. They may look slightly underdone but that’s ok!