Place the ingredients (except the garnish) in a high speed blender with 1 cup ice. Pulse until the ice is crushed. Pour into a glass and garnish with a pineapple wedge, maraschino cherry and cocktail umbrella.
To make the simple syrup: In a small saucepan, bring water to a boil. Add the sugar and stir until dissolved. Remove from the heat and set aside to cool. Pour into a sterilized bottle of jar. This simple syrup will keep in the fridge for up to a month.