Melt a little butter in a skillet and sauté the onions until tender. Set aside until later.
In a soup pot melt the ¼ cup butter. Add the flour and blend well until smooth and thick. Add the chicken stock and stir constantly until thick and smooth. Stir in half and half, raw seafood, corn, onions and salt and pepper. Cook until the shrimp are pink and done. Serve immediately.