Peanut Butter Cookies

8 Tbsp. (1 stick) unsalted butter, room temperature
3/4 cup smooth peanut butter
1/2 cup granulated sugar
1/2 cup packed dark-brown sugar
1 large egg
1/2 tsp. pure vanilla extract
1 cup all-purpose flour
3/4 tsp. baking soda
Dry-roasted, salted peanuts, for sprinkling (optional)

Preheat oven to 350 degrees. Line several baking sheets with parchment paper, and set aside.

In the bowl of an electric mixer fitted with a paddle attachment, cream the butter, peanut butter, and both sugars together until light and fluffy. Add the egg and vanilla, and mix on medium speed until well combined.

In a medium mixing bowl, sift the flour and baking soda together. Add to the butter mixture, and beat just to combine.

Scoop out 2 tablespoons of dough, shape into a ball, and place on one of the prepared baking sheets. Repeat with the remaining dough, placing scoops 3" apart. Dip the tines of a fork in warm water; press the dough balls lightly with the back of the fork to flatten them slightly (dip the fork back in the water for each dough ball, to prevent sticking). Sprinkle with a few peanuts, if desired.

Bake for 18-20 minutes, until golden brown, rotating the cookie sheets between the oven racks halfway through baking. Cool on wire racks and store in airtight container up to one week.

Note: These cookies can also be made with chunky peanut butter.

Makes 2 dozen

Recipe from Martha Stewart's Favorite Comfort Food cookbook.