Mustard's 3630 Katella Ave, Los Alamitos, CA90720 Mustard's is a Chicago-style eatery featuring Vienna 100 percent hot dogs. It claims to serve the dog that made Chicago…More famous. Toppings range from the classic chili and cheese to sauerkraut, Swiss cheese, hot peppers, and tomatoes. The restaurant also serves sandwiches, burgers, and salads. Mustard's offers more of cozy "Cheers" kind of ambiance that is missing in many large chain restaurants. The interior is filled with sports memorabilia, posters, and vinyl booths.