Start by squeezing your lemons until you've collected about a full cup of fresh juice — roll them on the counter first to get every last drop out, and strain out any seeds as you go.

Next, grab a small saucepan and combine the sugar with one cup of the water over medium heat, stirring until the sugar fully dissolves into a clear, smooth syrup. Take it off the heat and let it cool down before using it — adding hot syrup to cold water will just warm everything up.

Once your syrup has cooled, pour it into a large pitcher along with the fresh lemon juice and the remaining three cups of cold water. Give everything a good stir and taste it — if you'd like it a little sweeter or more tart, now's your chance to adjust.

Fill your glasses with ice, pour the lemonade over the top, and add a lemon slice or a sprig of mint if you're feeling fancy. That's all there is to it!