First, peel/zest two lemons. Set the zest aside for later.
Slice all the lemons & lime in half and squeeze out the juice.
Add sugar, water & lemon peel/zest to a medium-sized pot. Heat on medium heat until the sugar is completely dissolved (about 5 minutes).
Turn off the heat. Let the mixture cool down a little (about 5 minutes) and then pour in the fresh lemon juice that you squeezed earlier.
Pour the mixture through a fine-mesh sieve to remove any bits.
Lastly, carefully pour the mixture into an ice-cube tray*. Cover with a lid and place in the freezer for a few hours or overnight.
Notes
*If you don't have an ice cube tray, you can simply use ziplock bags instead. Simply fill them with the concentrate, close them properly, and then freeze them.Tip 1 - To make squeezing the lemon easier, press it down on a cutting board and use an open palm to roll it up and down the boardTip 2 - To preserve the nutritional benefits of freshly squeezed lemon juice, let the sugar syrup cool down at room temperature before adding the lemon juiceTip 3 - Drink through a straw. This can help protect your teethTO SERVE - Remove from the freezer and add a custom amount of still or sparkling water.I like to use a ratio of 2.5 to 1 (for example 2.5 cups of water to 1 cup of frozen lemonade concentrate). You can adjust this to taste.SUGAR-FREE - Use 1 teaspoon of stevia instead of sugar.