Cucumbers wash, peel and lengthwise halve. Dice 1 cucumber finely, chop the other one coarsely. Peel and chop the onion
Fry onion in 1 tablespoon of oil until translucent. Sauté cucumber pieces. Stir in 1/2 l water and stock, cover and simmer for about 10 minutes. Stir starch and 2 tbsp. water until smooth. Stir into the soup, simmer for about 3 minutes. Let cool off
Add 2/3 cucumber cubes, sour cream and buttermilk to the soup, puree finely. Season to taste with cayenne pepper, salt and vinegar. Chill for about 1 hour.
Dice the toast. Fry in 1-2 tablespoons of hot oil. Clean, wash and finely chop the bell peppers and spring onions. Wash and chop the dill. Season soup to taste, serve with the prepared ingredients and the rest of the cucumber.