- 1 tablespoon unsalted butter
- 1/4 pound Italian Fontina cheese, rind discarded, cut into 1/4-inch dice (3/4 cup)
- 1/2 cup milk
- 2 large egg yolks
- four 1/2-inch-thick slices from a large round crusty loaf of bread (about 8 to 9 inches across)
- 1 large garlic clove, halved crosswise
- 2 tablespoons extra-virgin olive oil
- 1/4 pound thinly sliced prosciutto
- 1 pound thin asparagus, trimmed and lower 2 inches of stalks peeled
- In a double boiler or a metal bowl set over a pan of simmering water melt butter. Add Fontina and milk and heat, stirring with a whisk, until cheese begins to melt. Whisk in yolks and cook, stirring constantly with whisk, until smooth and thickened slightly, about 7 minutes.
- Remove pan from heat and remove bowl from pan. Stir sauce 1 minute while water in pan cools slightly. Return bowl to pan and keep sauce warm over hot water (off heat), whisking occasionally to eliminate skin that forms on surface.
- Preheat broiler.
- On a baking sheet toast bread about 3 inches from heat, turning, until golden, about 1 to 2 minutes on each side. Rub tops of crostini with cut side of garlic and brush with oil. Season crostini lightly with salt. Divide crostini among 4 plates and top with prosciutto.
- In a deep 10- to 12-inch skillet bring 1 1/4 inches salted water to a boil and cook asparagus until crisp-tender, about 2 to 4 minutes. Transfer asparagus with tongs to a colander and drain. Divide asparagus among crostini. Pour fonduta over them.