Golden brown oatmeal cookies are extra moist thanks to a half-cup of peanut butter. Store cookies in the freezer for up to three months.
In a large mixing bowl, beat peanut butter and butter with an electric mixer on medium to high speed for 30 seconds. Add brown sugar, granulated sugar and baking soda. Beat in egg and vanilla. Beat in as much of the oats and flour as you can with the mixer. Stir in any remaining oats and flour. Stir in chocolate pieces. Cover and refrigerate dough about 1 hour or until easy to handle.
Shape dough in 1-inch balls. Place balls 2 inches apart on an ungreased cookie sheet. Flatten the cookies slightly.
Bake in a 350 degree F oven for 10 to 11 minutes or until edges are lightly browned. Transfer cookies to wire racks. Cool. Makes 4 dozen.
Place cookies in layers separated by pieces of waxed paper in an airtight container; cover. Store at room temperature for up to 2 days or freeze for up to 3 months. Thaw cookies, if frozen, before serving.