Wash and remove the stalks from the strawberries. If you picked the strawberries yourself, the fluffy hull would lift out as you pull of the stalk. Place the hulled strawberries in one of the bowls.
Crush the strawberries with a potato masher until you have a lumpy puree. If there is too much liquid, strain some away. This stops the fool from getting too runny.
Whip the lactose free cream in the other bowl with the rotary whisk until, when you lift up the whisk, the cream forms little mountain peeks.
Using a tablespoon, fold the crushed strawberries into the bowl of lactose free cream, using the spoon like a paddle, until the strawberries are all completely folded in and there is no more white lactose freecream. Add a squeeze of lemon juice, to taste.
How much icing sugar you need, depends on how sweet you like it. Sift in a little, heaped spoonful at a time, folding it in well. Keep tasting the mixture, until it is just right.