In a mixing bowl stir together flour, salt, cream of tartar, and baking soda. Set aside.
Using an electric mixer, cream together the butter and sugar on high speed until light and fluffy, about 2-3 minutes.
Reduce speed to medium and add the peanut butter, egg, and vanilla. Mix together until smooth and creamy.
Slowly add dry ingredients to the wet ingredients a cup at a time. Mix until well combined.
Using a wooden spoon or spatula, gently stir in chocolate chips and rice krispy cereal. Cover and chill the dough for 1 hour before proceeding. (Not chilling the dough will result in flatter cookies).
Preheat oven to 350° F. Line cookie sheets with parchment paper or silpat liners.
Roll dough into 1½ inch balls and place them on cookie sheets 2 inches apart.
Bake for 12-15 minutes or until the bottom of the cookies start to slightly brown. Cookies will be soft in the center.
Remove from oven and allow cookies to cool for 5 minutes on the cookie sheet. Transfer cookies to a cooling rack and allow them to cool completely.
Serve with a tall glass of ice cold milk.