Put a 9 or 25 cm metal cake pan in the freezer. In a blender, blend the strawberries, sugar, and lemon juice until the mixture is smooth and the sugar is dissolved. Add the ice cubes, blend the mixture until it is smooth, and pour it into the cold pan. Freeze the mixture for 30 to 40 minutes, or until it is frozen around the edge, but still soft in the center. Stir the strawberry ice, mashing the frozen parts with a fork, and spoon it into 2 bowls.