Cream of Cucumber Soup Potage Aux Concombres

Name: Cream of Cucumber Soup (Potage Aux Concombres)
Ingredients: 1 1/2 Pound cucumbers, about 3; 1/2 Cup minced shallots; 3 Tablespoons butter; 6 Cups light chicken stock, plus extra for thinning; 1 1/2 Teaspoon wine vinegar; 3/4 Teaspoons dried tarragon; 4 Tablespoons farina (cream of wheat) breakfast cereal; Salt and white pepper, to taste; 1 Cup sour cream; 1-2 Cup minced fresh dill, tarragon, or parsley