Preheat oven to 275°. Lightly butter two 4-oz. (1/2-cup) ramekins or ovenproof bowls and set in a baking pan just big enough to hold ramekins.
Slice asparagus thinly on the diagonal. Bring a small pot of water to a boil. Add asparagus; cook until just tender-crisp, 1 to 2 minutes, and scoop out into a colander. Keep water boiling, covered.
In a bowl, beat eggs with milk until smooth. Stir in cheese and salt. Divide mixture between prepared ramekins. Top each with half the asparagus and sprinkle with pepper.
Set ramekins in baking pan and put in oven. With oven door open, carefully pour hot water into baking pan up to the level of the eggs in ramekins. Bake until eggs are set in centers (touch to test), about 45 minutes. To remove ramekins, carefully pull oven rack out partway; lift ramekins from pan with tongs and set aside. Push rack with pan back into the oven to cool. Serve eggs immediately.
Buying Eggs. Quick Facts:
Pastured Eggs. What they are: Laid by chickens that spend most of their time outside, foraging on grass and insects. Price: Up to $7 per dozen. Where to find them: Farmers' markets; farm stands; a few markets (see localharvest.org or eatwild.com for sources near you).
Commercial Eggs. What they are: Laid by chickens typically fed a blend of grains, soy beans, and vitamins; birds are often confined to cages. Price: About $3 per dozen. Where to find them: Any grocery store.
Note: Nutritional analysis is per serving and using commercial eggs.