Preheat oven to 350ºF (180ºC).
In saucepan, heat 3 tablespoons (50 mL) vegetable oil over medium heat; cook flour, rosemary, 1/2 teaspoon (2 mL) salt and 1/4 teaspoon (1 mL) pepper, stirring, for
Gradually pour in milk; cook, whisking, for about 5 minutes or until smooth and very thick.
Remove from heat. Add cheese; stir. Let stand for 5 minutes. Whisk in egg yolks, 1 at a time.
In bowl, beat egg whites until stiff peaks form; fold one-quarter into cheese mixture. Fold in remaining whites. Spoon into 11- x 7-inch (2 L) baking dish.
Bake soufflé in oven for about 30 minutes or until puffed, golden and tester inserted in centre of soufflé comes out clean.