For the cold curry lentil soup, bake the bell pepper on a foil in the hot oven until the skin blisters and can be peeled off. Cook the lentils in the vegetable soup until almost tender in about 10 minutes. Add garlic and spices and finely puree half of the peeled and seeded peppers, including the liquid. Slowly stir in the buttermilk, season with pepper and salt and then refrigerate.
Finely dice the remaining peppers. Before serving, decorate the cold curried lentil soup with the bell pepper pieces and coriander leaves.