In a small saucepan, combine the brown sugar and water together. Place it over medium heat and bring it to a simmer, stirring occasionally. Continue to simmer until the sugar is completely dissolved, then remove it from the heat and allow it to cool.

Cut the lemons in half. Using a citrus juicer, juice the lemons until you have 1 cup of lemon juice. There will be some pulp, so you can strain the juice if you prefer your lemonade pulp-free.

In a pitcher, combine 2/3 cup of the brown sugar simple syrup, 2/3 cup lemon juice, and 4-5 cups cold water. For a chilled lemonade, add ice to the measuring cup before filling it with water, then add it to the lemon and sugar syrup.

Serve the lemonade over ice, garnishing with lemon slices and wedges as desired.

Store any leftover lemonade in a covered pitcher in the refrigerator.