Fluffy omelet with asparagus

For ➍
225 g asparagus, rinsed & tough ends snapped off
8 large eggs, separated
120 g shredded sharp cheddar cheese
6 cl milk
65 g all-purpose flour
½ ts cayenne or paprika
½ ts salt
1 tbs butter

Cut asparagus into 2-3 cm lengths. In a  pan over high heat, bring 25 cl to a boil. Add asparagus and cook until bright green and just tender when pierced, about 2 m. Drain, rinse with cold water, and drain again.
Meanwhile, in a large bowl, mix egg yolks, 4/5 of the cheese, milk, flour, cayenne, and salt until well blended. Stir in asparagus.
In another large bowl, with a mixer on medium speed, beat egg whites until stiff peaks form. Spoon about a quarter of the whites into yolk mixture; stir to combine. Scrape yolk mixture into bowl with remaining whites and fold together gently just to combine; do not overmix.
In an  ovenproof frying pan over medium-high heat, melt butter; swirl pan to coat. Pour in egg mixture and smooth top with a heatproof, flexible spatula. Cook until edges appear set and dry and bottom is browned (loosen edges with spatula to check), 7 to 8 m.
Transfer pan to oven and broil 10-12 cm from heat until omelet is puffed, set, and lightly browned, 3 to 5 m. Sprinkle evenly with remaining cheese; broil until cheese is melted and bubbling, 1 m longer. 
Serve at once from pan, spooning onto plates. 

Asian variant:
225 g asparagus, rinsed & tough ends snapped off
8 large eggs, separated
250 g scallions, chopped
6 cl miso stock
65 g all-purpose flour*
½ ts salt
1 tbs butter
Cut asparagus into 2-3 cm lengths. In a  pan over high heat, bring 25 cl to a boil. Add asparagus and cook until bright green and just tender when pierced, about 2 m. Drain, rinse with cold water. 
Meanwhile, in a large bowl, mix egg yolks, flour, scallions and salt until well blended. Stir in asparagus.
In another large bowl, with a mixer on medium speed, beat egg whites until stiff peaks form. Spoon about a quarter of the whites into yolk mixture; stir to combine. Scrape yolk mixture into bowl with remaining whites and fold together gently just to combine; do not overmix.
In an  ovenproof frying pan over medium-high heat, melt butter; swirl pan to coat. Pour in egg mixture and smooth top with a heatproof, flexible spatula. Cook until edges appear set and dry and bottom is browned (loosen edges with spatula to check), 7 to 8 m.
Transfer pan to oven and broil 10-12 cm from heat until omelet is puffed, set, and lightly browned, 3 to 5 m. Broil until cheese is melted and bubbling, 1 m longer. 
*Omit if wanted, use a thicker stock.