Twix Bar Cookies
1 (14 oz) can sweetened condensed milk
1 ½ sticks salted butter
¼ c white sugar
½ tsp pure vanilla extract
1 ½ c all-purpose flour
6 oz good quality dark or semisweet chocolate chips
For the caramel filling: Preheat the oven to 300F. Pour the sweetened condensed milk into a 9 by 9-inch glass baking dish. Cover with foil and place the dish inside a larger poaching pan. Add water to poaching pan until half way up sides of baking dish. Bake for 60-90 minutes (no need to stir) until thickened and caramel in color. Transfer to a bowl and beat until smooth.
For the shortbread: Preheat the oven to 350F. Cream together the butter, sugar, and vanilla until light and fluffy. Slowly beat in the flour and mix until just combined. Press the dough into a buttered 9 by 9-inch pan and bake for about 20 minutes, or until lightly golden. Allow it to cool on a wire rack.
Pour the warm caramel over the cooled shortbread and let it set and cool completely. Melt the chocolate either in a double boiler or in the microwave, then spread it over the cooled caramel. Allow the chocolate to set completely before cutting into squares.