Bisque of Frozen Peas and Corn

Cook corn and peas separately according to package directions. In a 1 1/2 quart saucepan, sauté onion in butter until soft. Put corn through a food mill, squeezing out hard skins, or spin in a blender, then strain out skins. Put peas in blender, add sautéed onion, using rubber spatula to scrape out all of butter, then spin until very smooth. Return to saucepan and stir in puréed corn, chicken stock, and cream; simmer for 3 or 4 minutes. Add salt and several turns of pepper grinder, to taste.