Add blue curacao, vodka, lemonade syrup with crushed ice in a cocktail shaker.
Shake it well.
Pour in serving glass and garnish with lemon slices and mint leaves.
To make lemonade syrup - Boil 1 cup lemon juice, 1 cup sugar and 1 cup water for few minutes till it thickens. Keep stirring so that sugar dissolves nicely. Let it cool down and store it.