Peanut Butter Sandwich Cookies

1 cup butter (room temperature)
1 cup creamy peanut butter
1 cup white sugar
1 cup packed brown sugar
1 teaspoon vanilla
3 eggs
4 cups flour
2 teaspoons baking soda
¼ teaspoon salt

Shape into 1" balls. Flatten with tines of fork. (Crisscross) Bake at 375 degrees 5 - 6 minutes.
5 dozen.

Put 2 cookies together with filling in between:
½ cup creamy peanut butter
3 cups powdered sugar
1 teaspoon vanilla
5 -6 tablespoons milk