Add sliced strawberries, peaches, water, sugar, and lemon juice to a saucepan

Bring mixture to a gentle boil over medium heat

Reduce heat and let simmer for about 15–20 minutes until fruit softens and releases flavor

Remove from heat and allow mixture to cool completely

Strain the mixture through a fine mesh sieve to create a smooth syrup

Pour syrup into a container and refrigerate until chilled

Fill a glass with ice cubes

Add about 2–3 tablespoons of prepared syrup into the glass

Pour sparkling water over the syrup and stir gently

Garnish with fresh fruit slices or mint if desired

Serve immediately for best flavor and fizz