Line cookie sheets with parchment paper or silicone baking mats. Set aside.
In a large bowl, beat butter and peanut butter together.
½ cup butter, ½ cup creamy or crunchy peanut butter
Add sugars, and beat until well-combined.
½ cup granulated sugar, ½ cup brown sugar
Mix in egg and vanilla until combined.
1 large egg, ½ teaspoon vanilla extract
Add flour, baking powder, baking soda, and salt. Stir until combined.
1 ¼ cups all-purpose flour, ½ teaspoon baking soda, ½ teaspoon baking powder, ¼ teaspoon kosher salt
Stir in chopped nuts and mini chips, if using.
½ cup chopped lightly salted peanuts, ½ cup semisweet chocolate chips
Cover, and chill dough for 1 hour, or until firm. Don't skip this step, or the cookies will bake out.
Toward the end of the chilling time, preheat oven to 350 F.
Scoop out 1.5 tablespoons of dough and place on prepared cookie sheet 2 inches apart. I've slightly flattened the cookies and left them as-is, and it doesn't seem to make much difference.
Bake 10-15 minutes, or until edges are lightly browned and middles are set.
Notes
Chocolate chips: You can use regular-sized, jumbo, or mini chocolate chips or chunks.