Wash the strawberries, cut them into little pieces and then blend them with the sugar and lemon juice. Cook the sauce over low heat until it has thickened.
Soak the Savoiardi biscuits in the sauce and place them in a clear glass baking dish. Cover the biscuits with a generous layer of whipped cream and the raspberries. Continue with another layer of Savoiardi soaked in the strawberry sauce and then the last layer of whipped cream and raspberries.
Leave it to chill in the fridge for about 3 hours before serving.