1 oz. Vodka
3 oz. Lemonade
1 oz. Blue Curacao
1 oz. Grenadine
Pour grenadine into a tall glass. Fill glass to the top with ice. Using the back of a spoon, slowly pour & cascade the Blue Curacao over the back of the spoon into the glass. Take your vodka & lemonade and put into a shaker that is filled with ice. Shake until chilled. Strain and slowly pour lemonade vodka mixture over the back of the spoon again, slowly cascading it over the blue layer.
Note: You may have to play around with your layers, depending on the density of your lemonade. The grenadine will be the most dense liquid so it will go on the bottom of the glass. Check the amount of grams of sugar in your vodka & lemonade, as compared to the Blue Curacao. Whichever has more grams of sugar will need to be your 2nd color layer. The least dense will be the top.