Hamburger and Sonic also rely heavily on hamburger sales. Fuddruckers and Red Robin are hamburger chains that specialize in the mid-tier "restaurant-style" variety of hamburgers. Some restaurants offer elaborate hamburgers using expensive cuts of meat and various cheeses, toppings, and sauces. One example is the Bobby's Burger Palace chain founded by well-known chef and Food Network star Bobby Flay. Hamburgers are often served as a fast dinner, picnic or party food and are often cooked outdoors on barbecue grills. A high-quality hamburger patty is made entirely of ground (minced) beef and seasonings; these may be described as "all-beef hamburger" or "all-beef
Rudolf Hamburger copies were sold. The East German authorities invited Rudolf Hamburger to exploit his new-found fame (if only as a bit-part player in his wife's success) by producing a volume of his own, but what was envisaged was a piece of propaganda controlled by the government, and Hamburger rejected the offer with an uncharacteristic absence of courtesy. He was nevertheless furious that Ursula's book concentrated on Ursula's espionage success. He felt that it unjustifiably played down his own contribution to their espionage partnership between 1930 and 1940. It may very well be that after this he redoubled his own work on