How to make the Long Island Milkshake – In a large blender Collins Glass, add Ice, Sugar cubes, Creme de Cacao, Vanilla Extract (optional), and the Cream or Half & Half. Mix for no more than 5-10 seconds. Then add the alcoholic beverages in no particular order, then hit the . frappe. ” or . “whip. ” button on the blender for 15-20 seconds. or until you can see that all the ingredients are well-blended but before you over-blend and start the Ice melting too fast. Serve in a tall pre-chilled Tom Collins or similar tall Iced-Tea glass. No garnish required. serve with a large-diameter straw.”