01 - Heat 1/2 cup water and 1/4 cup sugar in a small saucepan over medium heat, stirring constantly until sugar completely dissolves. Remove from heat and allow to cool to room temperature before using.
02 - Combine diced mango, halved strawberries, and fresh lemon juice in a blender. Process on high speed until completely smooth and no fruit chunks remain, approximately 1-2 minutes.
03 - Pour fruit puree through a fine mesh sieve into a large pitcher, using a spoon to press liquid through and discard solids for a smoother texture. Skip this step if you prefer a thicker consistency.
04 - Add cooled simple syrup (or alternative sweetener) and 3 cups cold water to the strained fruit puree in the pitcher. Stir thoroughly until all components are fully incorporated.
05 - Taste the lemonade and add more sweetener or water as needed to achieve your preferred balance of sweetness and tartness.
06 - Fill glasses with ice cubes, pour lemonade over ice, and garnish with fresh mint leaves and additional fruit slices. Serve immediately while chilled.