Peel asparagus and cut slantwise into 1-inch pieces. Place in saucepan with 1cup water and 1teaspoon salt. Cook till done, but it should still be almost crunchy and not soft. Drain.
Soak the roll in the milk, then squeeze. Thoroughly butter a pudding mold with 2tablespoons of the butter.
Whip the rest of the butter till foamy. Add the roll, egg yolks, sour cream and 1teaspoon salt. Whip till well mixed and fluffy.
Whip egg whites stiff and fold them in gently with a rubber spatula. Combine the mixture with the cooked asparagus; do it very carefully so as not to break the egg-white foam.
Pour the mixture into the buttered pudding mold. Do not fill mold more than three quarters full. Put on a tight-fitting top.
Fill a 4-quart pot half full of hot water. Set pudding mold into the pot and cook, with the cover on, for 1 hour.
To serve this as an appetizer sauté 1cup bread crumbs in ¼pound butter till golden brown; pour crumbs on top of pudding or spoon alittle over each slice. You may also combine the bread-crumb mixture with grated cheese.