Prep the Peaches: Wash, pit, and dice them. Skin on is fine. Less work, more flavor.
Make the Syrup: Add peaches, sugar, and ½ cup water to a saucepan. Cook over medium heat until soft, bubbly, and syrupy (about 7–8 minutes).
Blend Carefully: Transfer the hot mixture to a blender. Cover with a towel (seriously) and blend until smooth.
Strain (Optional): If you want it silky, strain out the solids. If not, keep it rustic.
Cool It Down: Let the syrup cool completely. Hot lemonade is not the goal.
Mix the Lemonade: In a pitcher, combine peach syrup, lemon juice, and 4 cups cold water.
Add Ice and Garnish: Toss in ice, peach slices, and lemon slices.
Stir and Serve: Give it a good mix and pour yourself a glass immediately.