Preheat oven to 350 degrees F.
I use perforated baking mats on my cookie sheets, which I highly recommend for evenly baked cookies and eliminating any potential spread.
In your mixer bowl cream butter, brown sugar, granulated sugar and peanut butter, until smooth, at least 2 minutes.
Beat in vanilla extract and eggs.
In a separate bowl, combine baking powder, salt and flour. Add to wet ingredient mixing bowl a little at a time.
Mix until thoroughly blended. Dough should be pulling away from the bowl.
Chilling the dough is not necessary! I have tried many different ways of rolling out dough and always come back to the old-fashioned way; a sheet of wax paper that has been floured.
I usually divide the dough into 3 chunks and roll out each onto a floured surface and cut. In my experience, this dough works best for cookies at 1/4" thick. I use my Joseph Joseph rolling pin which does the measuring for me – genius!
Bake at 350 for 8-9 minutes, depending on size of cookie. I also suggest baking similar-sized cookies together. You can bake longer if you prefer a crispier cookie.
Cool cookies on cookie sheet until firm enough to transfer to cooling rack.