Roll the lemons on a countertop with the palm of your hand to make them juicier. Slice the lemons in half and squeeze out the juice using a citrus juicer or by hand. Remove any seeds but leave some pulp for authenticity. You should get about 1 cup of lemon juice.

In a small saucepan, combine 1 cup of water and 1 cup of sugar. Heat over medium heat until the sugar fully dissolves, stirring occasionally. Remove from heat and let it cool to room temperature.

In a large pitcher, pour the lemon juice and the cooled simple syrup. Stir well to combine.

Add 4 cups of cold water to the pitcher. Stir and taste-test the lemonade. For more tartness, add extra lemon juice. For less tang, dilute with more water.

Refrigerate the lemonade for at least 1 hour to allow the flavors to meld. Serve over ice in glasses and garnish with lemon slices if desired.