Mae's Peanut Butter Cookies

1/2 cup shortening (1/2 butter)
1/2 cup peanut butter
1/2 cup sugar
1/2 cup brown sugar
1 egg
1-1/4 cup flour
1/2 tsp baking powder
3/4 tsp baking soda
1/4 tsp salt

Mix first 5 ingredients thoroughly. Add the remaining ingredients. Chill dough> Roll into balls the size of a large walnut. Place 3 inches apart on lightly greased baking sheet. Flatten with fork dipped in flour or water. Bake at 375 degrees until set but not hard.