|Butter/Margarine||1⁄3 Cup (5.33 tbs)|
|All purpose flour||1⁄4 Cup (4 tbs)|
|Dry mustard||1 Teaspoon|
|Skim milk||3 1⁄2 Cup (56 tbs)|
|Eggs||4 , separated|
|Asparagus||1 Pound, frozen (1 Package)|
|Boiling water||1 Cup (16 tbs)|
|Gruyere cheese||4 , diced|
1 Grease a 15x10x1 -inch jelly roll pan; line with wax paper; grease paper and dust lightly with flour.
2 Melt butter or margarine in a medium-size saucepan; blend in flour, mustard and salt; cook, stirring constantly, until mixture bubbles; stir in 3 cups of the milk. Cook, stirring constantly, until mixture bubbles 3 minutes and is very thick. Measure 1 cup sauce into a smallsaucepan; stir in remaining 1/4 cup milk and reserve.
3 Beat egg whites until they form soft peaks in a medium-size bowl with electric mixer at high speed. Beat egg yolks slightly in a large bowl; beat in remaining hot sauce, a spoonful at a time, until thoroughly blended. Fold in beaten egg whites until no streaks of white remain with a wire whip.
4 Bake in slow oven (325°) 35 minutes, or until golden and top springs back when lightly pressed with fingertip.
5 While omelet bakes, prepare asparagus: Break woody base off each stalk; soak asparagus in salted warm water 5 minutes to remove sand; lift asparagus out of water. Cut fresh or frozen asparagus into 2-inch pieces. Arrange in a large skillet; add boiling water and salt; cover skillet. Bring to boiling; lower heat. Simmer 15 minutes, or until crisply tender; drain.
6 Blend cheese into the 1 1/2 cups sauce in saucepan; heat slowly, stirring constantly, until cheese melts and sauce is smooth.
7 Remove baked omelet from pan this way: Loosen around edges with a spatula; cover with aluminum foil, then place a large cookie sheet or tray on top and quickly turn upside down. Lift off pan; peel off wax paper.
8 Spoon cooked asparagus in a single layer over omelet; drizzle with about 1 cup of the hot cheese sauce.