Try this:

4 tablespoons butter
1/2 cup chopped walnuts
1/2 cup finely chopped shallots
1/2 teaspoon minced garlic
1/2 cup dry white wine
2 cups whipping cream
1/4 cup chopped fresh basil
1/2 teaspoon salt
1/2 teaspoon freshly ground black pepper
1/4 cup freshly grated Asiago or Parmesan

Melt 2 tablespoons of the butter in large, heavy skillet over medium-high heat. Add the walnuts and cook, stirring, until brown and fragrant, about 3 minutes. Remove nuts from the pan. Add the remaining 2 tablespoons butter, shallots and garlic, and saute for 1 minute. Add the wine and cream, and bring to a boil. Cook over medium-high until the liquid has thickened and reduced by nearly 50 percent in volume, about 4 minutes. Stir in the basil, salt and pepper. Remove from the heat and cover to keep warm.

I've been to Trattoria ZaZa and cannot fault the quality of the food and service. In fact last time I was in Florence we went twice in a row! I would urge anyone who visits the city to have at least one meal there and don't miss the chicken liver pate!