1 (10 1/2-ounce) can frozen pina colada mix concentrate, thawed and undiluted
1/4 cup cornstarch
6 egg yolks
1 1/2 cups half-and-half
3 tablespoons butter or margarine, cut up
1 cup flaked coconut
1 teaspoon vanilla extract
Bring first 4 ingredients to a boil in a 3-quart saucepan over medium heat, whisking constantly. Boil, whisking constantly, 1 minute. Remove from heat; whisk in remaining ingredients.
Pour mixture into a bowl. Cover and chill at least 4 hours.