Warm 100 ml buttermilk lukewarm. Stir in the yeast and 1 teaspoon sugar and let rise in a warm place for 15 minutes.
Add the remaining sugar, flour, salt and the egg and the remaining buttermilk to the yeast mixture and stir everything into a semi-liquid batter. Let rise for about 45 minutes. Heat some butter in a pan. Bake small pancakes in it until the butter and batter are used up.
Bring the cherry juice to the boil with sugar. Mix the starch with a little water. Pour into the juice and bring to the boil for 1 minute. Stir in the cherries. Serve the finished pancakes dusted with powdered sugar.