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 - Add diced mango, halved strawberries, and freshly squeezed lemon juice to a blender. Process on high speed until completely smooth, scraping down sides as needed to ensure even blending.
03 - Pour the fruit mixture through a fine mesh sieve into a large pitcher, using a spatula to press through as much liquid as possible. Discard remaining pulp for a smoother texture.
04 - Add the cooled simple syrup and 3 cups cold water to the strained fruit puree in the pitcher. Stir thoroughly with a long spoon until all components are fully incorporated.
05 - Taste the lemonade and add more sugar or water as needed to achieve your preferred balance of sweetness and tartness. Stir again after any adjustments.
06 - Fill glasses with ice cubes, pour lemonade over ice, and garnish with fresh mint leaves, fruit slices, or lemon wheels. Serve immediately while cold.