Prep: Make mint simple syrup by simmering 1 cup of sugar and 1 cup of water until the sugar dissolves. Remove from the heat and stir in 1 ½ cups of mint leaves and let steep for 15 minutes. Remove the mint and let the syrup cool. Store leftover syrup in the fridge.
To make the drink: Combine 3 ounces lemon juice, 1 ½ ounce of the simple syrup, seltzer and fresh mint leaves. Finish with one shot of whiskey and lemon wedge. Let the sun shine.