rösti UK /ˈɹɜːstɪ/US /ˈɹɔsti/ noun1 •A traditional breakfast dish in Germanophone Switzerland (originally from Bern canton) made from potatoes, fried in a pan with butter or fat and widely varying other ingredients such as bacon, onions, cheese, apples or fresh herbs.The border between German- and French-speaking Switzerland is known as the “Röstigraben” because only the first traditionally serves rösti at breakfast. formsrostis · röstis