Preparation - Spread the macadamia nuts on a cookie sheet. Bake at 325º for about 5 minutes or until the nuts are lightly toasted. Lightly grease an 8" square baking pan; set aside. In a large mixing bowl, beat the egg and brown sugar together until light and fluffy. Add the melted butter and vanilla and mix well. Mix the flour, baking soda and salt together in a separate bowl. Add the dry mixture to the egg mixture. Stir just until blended. Coarsely chop the white chocolate. Stir the chopped white chocolate and toasted macadamia nuts into the batter. Pour the batter into the greased baking pan. Bake in a preheated oven at 325º for about 30 minutes, or until a toothpick inserted in the center comes out clean. Place on wire rack to cool. Cut into squares when completely cool.