Preheat oven to 350F.
Cream together butter and sugars.
Add in egg and vanilla and mix to combine.
In a separate bowl combine flour, cornstarch and baking soda
Add flour mix to wet ingredients and mix to combine.
Fold in chocolate chips and coconut.
Form dough in to teaspoon size balls and place on a greased cookie sheet.
Flatten balls slightly with the palm of your hand and top with sprinkles.
Bake for 8-10 minutes until cookies are golden around the outside.
Let cool on cookie sheet for 5 minutes then move to cooling rack and let completely cool.