From King Arthur Flour http://www.kingarthurflour.com/recipes/classic-peanut-butter-cookies-recipe
This recipe is a true gem with everything I expect in a great cookie chewy, tasty, and not too sweet. A great lunch box cookie. Here I sneak in 2 tablespoons of ground flax seed to bump up the nutrition. Very optional ingredient but a cookie jar staple. To extend the softness I place a single slice of bread in the bottom of the jar, as if they would last more than an hour in my house.
1/4 cup vegetable shortening
1/2 cup granulated sugar
1/2 cup light brown sugar
1 large egg
1 teaspoon vanilla extract
3/4 cup supermarket-style smooth peanut butter
1 1/2 cups Unbleached All-Purpose Flour
1 teaspoon baking soda
1/2 teaspoon salt
2 to 3 tablespoons water
1) Preheat the oven to 350°F. Lightly grease (or line with parchment) two baking sheets.
2) Beat together the shortening, sugars, egg, vanilla, and peanut butter till smooth.
3) Add the flour, baking soda, and salt to the peanut-butter mixture, beating gently till everything is well combined. Add enough water to make a cohesive dough.
4) Drop the cookie dough by tablespoonfuls onto the prepared baking sheets (a tablespoon cookie scoop works well here), leaving 2″ between them.
5) Use a fork to flatten each cookie to about 1/2″ thick, making a cross-hatch design.
6) Bake the cookies for 12 to 14 minutes, till they’re barely beginning to brown around the edges; the tops won’t have browned. Remove them from the oven, and cool on a rack.