Toffee Squares

1 cup butter (2 sticks) + more for coating the pan
1 cup brown sugar, packed
1 egg yolk
1 teaspoon vanilla
¼ teaspoon sea salt
2 cups all-purpose flour
1 ½  cups milk or semi-sweet chocolate, melted
½ cup chopped nuts such as pecans, sliced almonds, or chopped hazelnuts

1. Heat oven to 350°F. Grease a 10 x 15 x 1 inch pan with butter. Or you can use a rectangular cookie pan.
2. Place chocolate chips in a small, heavy saucepan over the lowest heat setting on the stove. Heat gently until melted and smooth.
3. Cream the butter and sugar together. Beat in the egg yolk, vanilla, salt, and flour until combined and smooth. Spread in prepared pan. (If using a rectangular pan, spread it only to 15 inches square.) Bake about 20 – 25 minutes or until very lightly browned. While it’s still hot, spread with melted chocolate. Sprinkle evenly with chopped nuts. Cool completely and cut into small squares or break into irregular pieces.