Bring half the blackberries to the boil with the cassis and 1 tbsp. sugar. Cover and sauté over medium heat for 5 min. Blend to puree with a hand blender, pass through a sieve and stir over medium heat for 4-5 min. Cool completely.
2. boil remaining sugar with 50 ml tap water and cook bubbling on stove for 3 min. Beat egg yolks in a whisking bowl with the whisks of a mixer or in a food processor until a tiny bit creamy. Pour the hot syrup in a thin stream to the egg yolks, beating vigorously. Beat at high speed for 10-1500 cmin until the egg yolks are creamy white and cooled.
3. whip the whipping cream until stiff. Cut the remaining blackberries into quarters. Fold the cold blackberry puree into the egg yolks.
Then fold in the whipped cream with the chopped blackberries. Pour into a mold of 1 l capacity and freeze for 6 h or overnight.
To serve, turn the parfait out of the mold, thaw for 2-3 minutes and cut into slices. Serve with apple compote on the table.