Preparation

• Position a rack in the center of the oven and heat the oven to 400°F. Butter the inside of a straight-sided round baking dish that’s about 2-1/2 inches deep and holds 6 to 7 cups. Combine the breadcrumbs with 1 Tbs. of the Parmigiano. Coat the inside of the dish with this mixture, tapping out any excess

Make the base:

• Melt the 3 Tbs. butter in a medium saucepan over medium heat. Whisk in the flour and cook until the flour just starts to turn golden brown, about 2 minutes. While whisking constantly, pour in a little of the milk. As soon as it thickens (which will be almost immediately), pour in a little more milk. Continue whisking and gradually adding milk in this way until all the milk is added and the sauce is smooth. Adjust the heat to a very slow simmer and whisk in the mustard, Worcestershire, Tabasco, and 1/2 tsp. salt. Simmer for 5 min. The sauce will be very thick; whisk frequently to prevent scorching. Whisk in the Gruyère and Asiago until mostly melted and remove the pan from the heat.

Separate the eggs:

• Collect the five egg whites in a large clean bowl. Add four of the yolks, one at a time, to the cheese sauce. Whisk in each yolk as you add it; discard the remaining yolk or save it for another use. Be sure that no traces of yolk get into the whites.

Whip and fold in the whites:

• 加一点盐和一撮酒石酸氢钾to the whites and beat with an electric mixer (preferably a hand-held) on medium-low speed until the whites are frothy. Increase the speed to high and continue beating until you get almost stiff peaks. Immediately, gently whisk about one-fourth of the whites into the cheese sauce to lighten it. With a rubber spatula, scrape the sauce into the part of the bowl where you removed onefourth of the whites and gently fold the sauce into the remaining whites with the spatula until the whites are almost completely incorporated (a few small areas of white are fine). Scrape the mixture into the baking dish and sprinkle the remaining 3 Tbs. Parmigiano over the top

Bake the soufflé:

• Put the baking dish in the oven and immediately reduce the temperature to 375°F. Bake until the soufflé is puffed and deeply browned, 25 to 30 min. (don’t open the oven door for at least the first 20 min.). Serve immediately; the soufflé will begin to collapse almost as soon as you take it out of the oven.