Whip the ricotta with sugar and 3 tablespoons of the sambuca until creamy. Carefully fold in the double cream. Then pour the cream into a serving bowl and place in the refrigerator for at least 4 hours.
Just before serving, heat the rest of the sambuca in a small pan, pour it over the chilled ricotta cream and light it up with a match. As soon as the flames have gone out, place the well-cooled berries on top of the cream.
Garnish with white chocolate chips if you like and serve immediately.