Sift together flour, baking soda, baking powder and salt.
Cream together peanut butter, shortening and sugar.
Mix in egg and vanilla.
Add dry ingredients. Do not over-mix.
Roll dough into 1 inch balls.
Place on cookie sheet and flatten with fork tines dipped in water.
Leave tine marks on surface of cookies.
Bake in pre-heated 375 degrees oven 8 to 10 minutes.
Cool slightly before removing from pan.
Cool on rack.