Heat your oven to 350°F
Sift the flour, baking soda, baking powder, and salt into a small bowl.
1¼ cup (156 grams) bleached, all purpose flour, ¾ teaspoon baking soda, ½ teaspoon baking powder, ¼ teaspoon salt
Using a mixer, cream the butter, peanut butter, and sugars together on medium speed for at least a couple of minutes until light and fluffy.
1 cup (264 grams)creamy peanut butter, 8 tablespoons (1 stick or 4 ounces or 113 grams) unsalted butter, softened, ½ cup (110 grams) dark brown sugar, packed, ½ cup (100 grams) granulated sugar
Add the egg and mix for one minute on low speed, and then add the milk and vanilla and mix again for one minute.
1 egg, room temperature, 1 tablespoon whole milk, 1 teaspoon vanilla
Add the flour mixture and mix until just combined.
Add the peanut butter chips and chocolate chips and mix by hand.
½ cup peanut butter chips, ½ cup chocolate chips
Using a spoon or a medium cookie scoop (#40), scoop 2 tablespoon balls of dough onto a lined cookie sheet, spacing them at least 2 inches apart.
Bake for 10 to 12 minutes, until the cookies are just barely starting to harden and the edges just starting to barely brown. Do not over-bake!
Cool on the baking sheet for a few minutes then transfer to a cooling rack to cool completely.