Summarize this article in one sentence.
Remove the leaves from each strawberry. Clean them as needed. Add a few ice cubes. Add sufficient water to cover the strawberries and cubes. Blend all the ingredients to combine. Taste a little, then sweeten to taste with the sugar.  Stir with a long-handled spoon.

Summary:
Prepare the strawberries. Place the strawberries into the blender. Pour in the lemon juice. Drop in the mint leaves. Fill a pitcher or jug halfway with ice cubes. Pour the blended slushie into the pitcher or jug. Serve immediately.