Base
1/2 cup firmly packed brown sugar
1/2 cup butter, softened
1 1/2 cups flour

Toffee Filling
1 can sweetened condensed milk
1/2 cup butter
2 tablespoons corn syrup
1 teaspoon vanilla extract

Chocolate Drizzle
3 ounces bittersweet chocolate, broken into pieces

Preheat oven to 325 degrees F.

Base: With an electric mixture, beat sugar and butter until fluffy. Gradually beat in flour until well combined. Press mixture into bottom of an 8inch square pan. Bake for 30 minutes until golden brown.

Toffee Filling: Mix sweetened condensed milk, butter and corn syrup and cook stirring over medium low heat for 5 minutes or until bubbly. Remove from heat and stir in vanilla extract. Pour toffee over baked base. Bake for 25 to 30 minutes or until golden. Cool completely.

Chocolate Drizzle: Melt chocolate until smooth. Drizzle over the filling. Chill and cut into bars.