Spread macadamia nuts in a single layer in a greased 15x10x1-in. baking pan. Bake at 250° for 5 minutes; set aside.
In a heavy saucepan, combine 6 tablespoons sugar, corn syrup, oil and salt; bring to a boil, stirring constantly. Boil without stirring until a candy thermometer reads 238° (soft-ball stage).
Remove from the heat; stir in butter until melted. Pour over nuts; stir to coat. Bake for 50-55 minutes or until lightly browned, stirring occasionally. Sprinkle with remaining sugar; toss to coat. Spread on foil to cool. Break apart and store in an airtight container.