Mix flour and milk and beat until smooth. Add sugar and salt. Break eggs into the mixture and stir gently until thoroughly mixed.
Rosettes (which must be made in special irons - available in the housewares departments of large department stores or restaurant supply houses) must be deep-fried. Heat fat in a small, deep pan, somewhat larger than the head of the rosette iron, containing about 2½ inches of cooking oil. Dip iron first into hot fat, then into batter, without letting batter run over top of the iron. Transfer batter-filled iron to the fat; submerge it totally for 25 to 35 seconds. Remove rosettes from pan, reheat pan, and repeat process until all batter is used.
Drain on paper towels and roll in sugar.