Position a rack in the center of the oven and heat the oven to 325°F. Butter an 8x8-inch baking dish.
In a 12-inch nonstick skillet, cook the bacon over medium heat until crisp, about 8 minutes. With a slotted spoon, transfer the bacon to a large bowl. Add the leeks to the skillet, reduce the heat to medium low, cover, and cook, stirring occasionally, until softened, about 4 minutes. Add the leeks to the bacon and stir in the thyme and 1/4 tsp. each salt and pepper.
Gently warm the milk in the skillet over medium-low heat. Stir in the cream cheese and Asiago and whisk until melted and combined. Add the milk mixture to the leeks and bacon and stir to combine and cool slightly. Gently mix in the egg yolks; set aside.
In a medium bowl, beat the egg whites and cream of tartar with an electric hand mixer on high speed to medium-stiff peaks. With a large spatula, gently fold the egg whites into the leek and bacon mixture.
Pour the mixture into the prepared dish and bake until puffed and golden-brown on top, 22 to 24 minutes. Serve immediately—the soufflé will deflate as it cools.
Serve this with a green salad for brunch.
nutrition information (per serving):
19, Fat Calories
170, Saturated Fat
13, Monounsaturated Fat
7, Polyunsaturated Fat
Photo: Scott Phillips