Measure 1 cup (250 ml) water into jar of high speed blender. Add lemon juice and maple syrup. Add hulled strawberries until they go up approximately to the 3-cup mark on the blender. Blend until smooth. This is a good time to taste the purée to adjust sweetener to your liking.
1 cup water, 1 lemon (juice), 1 tablespoon pure maple syrup, 3 cups fresh strawberries
Add the ice and pulse the blender just a few times until the ice is broken into a nice slushy consistency.