3. Combine wet ingredients. In a second mixing bowl stir together the melted butter and sugars. Add in your eggs and vanilla. Mix to combine. Whisk in peanut butter until smooth and combined.
6. Scoop the cookies. Using a small cookie scoop, or tablespoon scoop the cookies into 1 ½-inch balls (about 2 tablespoons) onto prepared baking sheets about 2 inches apart. (For larger cookies I use a large scoop that holds about 1/4-cup of cookie dough and place 6-8 on a baking sheet).
7. Bake and cool the cookies. Bake cookie sheet on the middle rack for 10-12 minutes, until lightly browned on the sides and edges are set. (For larger cookies bake 15-17 minutes). The centers will look soft. Remove from the oven and let cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely. Remove from the cookie sheet and allow to cool on a cooling rack.