Remove caviar from the scallops, set aside. Melt butter and pass shallots. Put the scallops and cook until soft, covered for about 1 minute, add caviar, cook for another minute. Remove scallops and caviar, keep them warm. In a frying pan pour dry white wine, pour the broth, boil down. Add sour cream and saffron, simmer until thick. Pour the sauce on the plates, put the scallops with caviar and serve.