"The Slaves Of Spiegel" by Daniel Pinkwater.

This book is about a man named Steve Nickelson and a boy named Norman Bleistift who were kidnapped by junk food craving aliens from the planet Spiegel and forced to cook for them. Steve and Norman both worked as cooks and managed a restaurant called the Magic Moscow in Hoboken, New Jersey. The Magic Moscow was an extraordinary restaurant because it featured ice cream sundaes which contained pizza dough, lobster, vegetables, and other peculiar ingredients. It also sold hamburgers, deep fried pumpkin rinds, salads, and other foods, including sixteen flavors of ice cream. The aliens went to…