Coconut-peanut toffee
-1 1/4 unsalted butter cut into chunks, plus more for pan
-3 1/3 cups sugar
-3/4 cup water
-1/4 cup corn syrup/molasses
-1/2 teaspoon salt
-1 cup toasted unsalted peanuts(about 5 ounces), finely chopped
-1/2 cup unsweetened dried coconut
-2 teaspoons vanilla extract
= lightly butter a 10-by-15 inch jelly roll pan