Wash and roll 4–6 lemons to release juice
Cut lemons in half and juice them into a pitcher
Add 1 cup sugar (or to taste)
Pour in 4–6 cups cold water, starting with 4 cups
Stir until sugar fully dissolves
Taste and adjust with more sugar or lemon juice as needed
Add ice if serving immediately
Stir again and garnish with lemon slices if desired
Serve cold