8 tablespoons (1 stick) unsalted butter
1 cup whole peeled roasted chestnuts (from 7.4-ounce jar)
2 tablespoons chopped fresh thyme
3 cups whole milk
1/4 teaspoon salt
1 cup pasta flour (golden semolina flour)*
1 1/4 cups (packed) coarsely grated Fontina cheese (about 5 ounces)
5 large eggs, separated

Preheat oven to 350�F. Butter 11x7-inch glass baking dish. Melt 2 tablespoons butter in heavy medium skillet over medium heat. Add chestnuts and thyme.
Saut� until heated through, breaking chestnuts into 1/2-inch pieces with back of spoon, about 4 minutes. Bring milk just to simmer in heavy large saucepan over medium-high heat. Add salt, then gradually whisk in pasta flour. Reduce heat to medium. Cook until mixture is very thick, stirring constantly, about 3 minutes. Remove from heat. Add remaining 6 tablespoons butter, then 1 cup cheese, whisking until cheese melts. Whisk in egg yolks 1 at a time; stir in chestnuts. Beat egg whites in large bowl until stiff but not dry. Fold whites into warm flour mixture in 2 additions. Transfer to prepared dish; sprinkle with remaining 1/4 cup cheese. Bake spoon bread until puffed and beginning to brown, about 35 minutes. Let cool 5 minutes; serve warm.
*Available at specialty foods stores, Italian markets, and some supermarkets.