Very little preparation but lots of taste.
1 (19.5-ounce) package brownie mix
2 cups quick-cooking oats
½ cup (1 stick) margarine, melted
1 cup white chocolate chips
1 cup semisweet chocolate chips
Preheat oven to 350 degrees. Beat together brownie mix, oats, melted margarine and eggs. Stir in chocolate chips. Drop by ¼-cupfuls onto greased cookie sheets. Bake for about 15 minutes. Cool 1 minute on cookie sheet before removing to wire rack to finish cooling.
My favorite easy cookie recipe based on a cake mix is this one  calling for chocolate chips and coconut.