1 c whole unsalted blanched almonds butter, cut into bits 1 c unsalted broken black-walnuts 1½ c sugar ½ c whole unsalted filberts 1 c light corn syrup 1 tsp salt 1/3 c water 1 T butter, softened, plus 2 T of 1 tsp vanilla extract ----------------------Preheat the oven to 350°. Mix the almonds, black walnuts, filberts and salt in a large shallow baking dish. Toast the nuts in the middle of the oven for about 5 minutes, stirring them from time to time. Then turn off the heat, but leave the nuts in the oven to keep them warm.
With a pastry brush, spread the tablespoon of softened butter over a large baking sheet and set it aside. Combine the sugar, corn syrup and water in a heavy 2- to 3-quart saucepan and bring to a boil over high heat, stirring until the sugar dissolves. Then cook briskly, uncovered and undisturbed, until the syrup reaches a temperature of 290° on a candy thermometer or until about 1/8 teaspoon of the syrup dropped into ice water immediately separates into hard but not brittle threads.
Remove the pan from the heat and immediately beat in the 2 tablespoons of butter bits, the vanilla and the warm nuts. Pour the candy onto the buttered baking sheet and set it aside to cool to room temperature. Break the mixed nut brittle into pieces with a kitchen mallet or your hands, and store in a tightly covered jar until ready to serve. Makes about 2 pounds.