Oatmeal Chocolate Chip Peanut Butter Cookies

1 cup (2 sticks) unsalted butter, softened to room temperature

3/4 cup creamy peanut butter

1/2 cup sugar

1/2 cup brown sugar

2 large eggs

1 teaspoon vanilla extract

1 1/4 cups all-purpose flour

1 cup old fashioned rolled oats

1/2 teaspoon baking powder

1/2 teaspoon baking soda

1/2 teaspoon salt

2 cups (12-ounce package) semisweet chocolate chips

Place an oven rack in the middle position and preheat the oven to 350°F.

Put the butter, peanut butter and the sugars in a large bowl. Beat with an electric mixer or a wooden spoon until smooth and creamy. Add the eggs and vanilla and beat again. Add the flour, oats, baking powder, baking soda and salt, and beat on low speed until well blended. Add the chocolate chips and mix thoroughly.

Using a teaspoon as a guide, scoop a portion of the dough and, with your hands, roll each portion into a ball. Place the balls on each cookie sheet, about 16 on a sheet. Flatten the balls with the heel of your hand or the tines of a fork so that they spread to about 1 1/2 inches in diameter. Bake each batch, one cookie sheet at a time, for about 10 minutes. The cookies will be firm to the touch and just beginning to brown.

Remove from the oven and cool on the sheet for about 3 minutes. Then transfer them with a spatula to a cooling rack. Let the cookie sheet cool for 1 or 2 minutes more before reusing so the dough doesn't melt. Store in an airtight container.