In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and sugars until light and fluffy. Add the eggs, one at a time. Add the vanilla and peanut butter, and mix. Sift together the flour, baking powder, and salt and add to the batter, mixing only until combined. Fold in the chocolate chunks.
Drop the dough on a baking sheet lined with parchment paper,
using either a 1 3/4-inch ice cream scoop or a rounded tablespoon.
Dampen your hands, flatten the dough lightly, then press the tines
of a wet fork in both directions. Bake for exactly 17 minutes
(the cookies will seem underdone). Do not overbake. Remove
from the oven and let cool slightly on the pan, then transfer to a
wire rack and let cool completely.
Makes 36-40 cookies