In a saucepan, heat 1 cup of water and granulated sugar on medium heat. Cook just until the sugar dissolves. Remove heat and allow it to cool.
Cut the lemons in half and juice the lemons with a juicer or hand squeezer. (Remove any seeds from the lemon juice.)
Add the rest of the water, cooled simply syrup and lemon juice to a pitcher and stir until well combined. (Adjust the lemonade if you want it to be sweeter or lemonier.)
Remove the leaves off of the strawberries, rinse and then quarter the strawberries.
Add the strawberries, mint leaves, and sugar to a blender and blend until pureed.
Place a strainer over a bowl or measuring cup and strain the puree. (Or just strain straight into the pitcher to avoid more dishes.)
Pour in the strawberry mixture into the pitcher of lemonade and mix to combine.
Add ice cubes, mint leaves, and additional lemon and strawberry slices to the pitcher, stir to combine and serve.
Notes
Mashed Strawberries-
Remove the leaves off the strawberries, rinse and then quarter the strawberries.
Add the strawberries, mint, and sugar to a bowl and with a muddler or masher mash the strawberries, allow the juices to be released.
Pour the strawberry mixture into the lemonade, mix and serve.