From Food and Wines of France, Inc.
Melt butter in large, heavy Dutch oven over moderately high heat and saute onion for 1 minute; cover; sweat for 10 minutes. Meanwhile, halve and core the cauliflower. Reserve some flowerets and chop remainder to total about 6 cups. Peel and dice potato. Add cauliflower and potato to Dutch oven; cook, stirring, for 1 minute. Add chicken broth, chives, Herbes de Provence and red pepper seasoning. Bring to boil; cover; lower heat and simmer for 10 minutes, or until vegetables are just tender. Cool slightly. Puree all but 1 1/2 cups mixture in food processor or blender in batches; return to pan. In a small bowl, blend cream, yolks and Armagnac; add 1 cup of the hot soup, beating constantly with wire whip. Return to pan; add half of crumbled Roquefort. Heat very slowly, stirring constantly, until cheese melts and soup thickens slightly. Do not allow soup to boil. Garnish soup with reserved cauliflowerets, crumbled Roquefort and chives.
Makes 4 to 6 servings.