Select a deep rectangular 1-litre container, something like a lunch box or small loaf tin, and lightly oil the inside. (The semifreddo will later be unmoulded and sliced.)
Pour the cream into a measuring jug.
Weigh the frozen berries and sugar into the Thermomix bowl and blend 10 seconds/speed 9.
Add the condensed milk and a dash of the cream to loosen the mixture and blend 5 seconds/speed 9.
Insert the Butterfly. Add the remaining cream and mix 20 seconds/speed 4.
Scrape down the bowl and mix a further 5 seconds/speed 4.
Turn the mixture into the prepared container and freeze overnight
Scoop from the container, or to be more dramatic, unmould the semifreddo and cut into 6–8 slices with a warm knife, placing the slices straight onto a plate.
Allow to stand for 5 minutes or so to soften slightly then serve with fresh raspberries, an almond tuile (page 56) dusted with icing sugar and passionfruit sauce. It’s also delicious in a simple cone.
AND … Condensed milk comes in 395-gram tins or 200-gram tubes. If using a tin, half will be left over but this can be refrigerated or frozen, or you could make a second batch of semifreddo