Place the chopped peaches, 2 cups of water, and 1 cup of sugar in a medium saucepan. Bring the mixture to a boil over high heat, then adjust the heat to maintain a simmer. Simmer for 10 to 15 minutes or until the peaches are softened.
Take the saucepan off the heat and let the mixture cool. Once it’s cooled off, strain the syrup through a fine mesh sieve and discard the solids.
Place ice cubes in a pitcher. Add the lemon juice, peach syrup, and 3 cups of water. Stir to combine.
Pour the lemonade over ice in glasses. Garnish with mint and sliced peaches, if using.
Notes
Make ahead tip: You can make the peach syrup ahead and keep it in the refrigerator. It will keep for several weeks in an airtight container. You can also mix the syrup with the lemon juice and water and chill the lemonade in the fridge until you're ready to serve it. Wait to add the ice until you serve it.If you don't have fresh peaches, you can use thawed frozen peach slices or canned peaches (be sure to drain them).