Perfect Lemonade (Real Lemons and Sugar)

Make simple syrup by heating the sugar and 1 cup water in a small saucepan until the sugar dissolves completely.
While the sugar is dissolving, juice the lemons.
Add the juice and the sugar water to a pitcher. Add 3 to 4 cups of cold water, more or less to the desired strength.
Refrigerate 30 to 40 minutes. If the lemonade is a little sweet, add a little more juice.
Serve with ice and sliced lemons.