Gather the ingredients. Preheat the oven to 350 degrees F (175 degrees C).

Mix butter, oil, brown sugar, white sugar, egg, vanilla, cream of tartar, baking soda, and salt together in a large bowl until smooth; stir in flour, crisp cereal, oats, coconut, and chocolate chips to form a dough.

Roll dough into walnut-size balls and place 2 inches apart on baking sheets. Press cookies down with a glass which has been buttered and dipped in sugar.

Bake cookies in the preheated oven until edges are golden, about 12 minutes. Cool on the baking sheet briefly before removing to a wire rack to cool completely.