For the kefir with blackberries, defrost the blackberries. Set aside 75 g blackberries, finely puree the rest and pass through a sieve. Sweeten with half of the powdered sugar.
Mix the coconut cream, kefir and vanilla sugar. Season with grated lemon zest and juice of one lemon. Pour into dessert bowls and garnish with a few remaining berries. Chill for about 1/2 hour before serving.