Twix Bar Cookies {aka Millionaire's Shortbread)
Prep time: 
Total time: 
Yield: 1 (9 by 9-inch) pan, about 16 to 24 servings
 
Ingredients
  • 12 tablespoons (1½ sticks) unsalted butter, at room temperature
  • ¼ cup white sugar
  • 1 tsp pure vanilla extract, divided
  • 1½ cups all-purpose flour
  • ¼ + ⅛ teaspoons salt
  • 1 (14 oz) can sweetened condensed milk
  • 6 oz good-quality dark or semisweet chocolate (I use 65% cacao)
Instructions
  1. For the shortbread, preheat the oven to 350F; line a 9 by 9-inch pan with 2 pieces of parchment paper so that the paper hangs over the edges. Cream together the butter, sugar, and ½ teaspoon vanilla until light and fluffy. Add the flour and salt and stir to combine. Press the dough into the prepared pan and bake until lightly golden, about 20 minutes. Cool on a wire rack.
  2. For the caramel filling, add the sweetened condensed milk and remaining ½ teaspoon vanilla to a heatproof bowl set over a saucepan of simmering water (make sure the water level is low enough so that it isn't bubbling up onto the bottom of the bowl; periodically check the water level and add more as necessary so the pan doesn't run dry). Drape a piece of aluminum foil over the bowl and cook until the sweetened condensed milk is thickened and light caramel in color, about 60 to 90 minutes, stirring occasionally. If lumpy, transfer to a bowl and beat until smooth. Spread the caramel as evenly as possible onto the cooled shortbread and let the caramel cool to room temperature.
  3. Once the caramel is cool, melt the chocolate in a double boiler or microwave. Evenly spread the chocolate over the cooled caramel, and allow it to set before cutting into squares.
  4. Store leftovers wrapped in the fridge for up to 1 week.
Notes
Recipe adapted slightly from the recipe for Millionaire's Shortbread on Joy of Baking.
Recipe by An Edible Mosaicâ„¢ at https://www.anediblemosaic.com/twix-bar-cookies/