Puree the strawberries in a blender or food processor.
Strain the puree through a fine-mesh sieve, if desired, to remove the seeds.
In a small saucepan over medium heat, combine the sugar and 2 cups of water.
Bring to a boil, stirring until the sugar has completely dissolved.
Remove from the heat and allow the simple syrup to cool to room temperature.
Strain the fresh lemon juice into a 2-quart pitcher.
Add the cooled simple syrup and strawberry puree, then stir until well combined.
Refrigerate until thoroughly chilled.
Just before serving, stir in 2½ cups of cold water. Taste and add additional water if you prefer a less sweet lemonade.
