Preheat oven to 350°F (177°C).
Lightly grease and line an 8-inch square baking pan with parchment, leaving a 2-inch overhang on all sides for easy unmoulding.
In a medium bowl, whisk together the all-purpose flour, Redpath® Granulated Sugar, cornstarch, and salt until well combined and no lumps remain. Create a well in the center of the dry ingredients.
Pour the melted butter, Irish cream liqueur, and vanilla extract into well. With a rubber spatula fold together until it forms a dough; do not overmix.
Transfer and evenly press the soft dough with the spatula into the prepared pan. Dock the dough with a fork and place into the fridge to chill; 10 minutes.
Place chilled shortbread base into the preheated oven and bake for 25 to 30 minutes, or until pale golden and edges are golden brown in colour. Remove from the oven and place onto a wire cooling rack to cool.
In a heavy-bottomed saucepan, combine sweetened condensed milk, the Redpath® Dark Brown Sugar, cubed butter, and honey. Place over medium heat and continuously stir with a heat-proof spatula until mixture becomes homogeneous and comes to a boil.
Reduce heat to medium-low. Keep stirring to prevent milk from burning onto the bottom of the pot; 20 minutes. The caramel is ready when the colour changes from a creamy beige to a deep amber colour, caramel is reduced and thickened, and distinct paths are formed (bottom of pot is visible) when running the spatula across the bottom and sides of the pot.
Turn off heat and carefully stir in the Irish cream liqueur, vanilla extract, and salt until well combined. Pour and evenly spread the caramel over the cooled shortbread base. Gently tap pan on work surface to help even out the caramel.
Let cool at room temperature for about 15 minutes before placing into the fridge to chill completely; 45 minutes.
Remove the chilled bars from the fridge. Allow bars to come to room temperature while making the glaze. This keeps the chocolate from solidifying immediately upon contact with a cold surface.
Place a medium pot with about 2 inches of water over medium heat. Bring to a boil. Reduce temperature to low; water should be barely simmering.
In a medium heatproof bowl (bowl should fit over the pot, but should not come in contact with the water), combine the chopped chocolate, Irish cream liqueur, and espresso powder. Place the bowl over the pot and slowly stir until chocolate is almost completely melted. Remove from heat, wipe away any moisture off the bottom of the bowl, and stir until chocolate is completely smooth and slightly cooled.
Quickly pour and evenly spread the chocolate glaze over the caramel layer using a small offset spatula to help. Gently tap pan on work surface to help even out the chocolate layer.
Place pan into the fridge to allow chocolate layer to harden; 20 to 30 minutes.
If planning on using edible gold leaf, chill bars until chocolate is completely hardened before applying. (See Chef’s Tips for more details.)
If using sprinkles or flaky sea salt, remove bars after 5 minutes in the fridge and sprinkle the top with sprinkles or flaky sea salt. Place back into the fridge to set.
Run a small offset spatula around the bars and the parchment paper, pressing the blade against the parchment paper to prevent gouging of the bars. Clean the offset spatula, and run it around the parchment paper and the sides of the baking pan, pressing the blade of the offset spatula against the sides of the pan. This will help loosen the parchment paper from the pan, and loosen the bars from the parchment paper.
Carefully score bars before cutting with a sharp chef’s knife. Store bars in an airtight container layered between parchment paper, in a cool, dry location for up to a week or in the fridge for up to 2 weeks.
*Redpath® Golden Yellow Sugar can be used in place of the Redpath® Dark Brown Sugar, though the resulting caramel will be lighter in colour, and have a milder butterscotch flavour.
*Irish cream can be replaced with Irish whiskey or another type of liqueur, if desired.
*Omit Irish cream liqueur and replace with heavy cream if an alcohol-free bar is needed. Add an additional teaspoon (5 ml) of pure vanilla extract or ½ teaspoon (2 ml) of pure almond extract to the shortbread base. For the caramel layer, add the heavy cream with the condensed milk.
*Do not increase heat when making the caramel layer. Heating the ingredients too quickly can result in the butter separating from the caramel. If this happens, remove from heat and use a whisk to quickly whisk the mixture back into emulsion. Reduce temperature, before placing back onto the heat.
*Do not use chocolate chips for the glaze as they are formulated to stay as “chips” and not melt as smoothly as baker’s (couverture) chocolate or high-quality chocolate.
*Ensure when melting the chocolate that the water in the pot is not boiling. Slowly and gently warming the chopped chocolate with the Irish cream liqueur will prevent the chocolate from splitting, and also prevent the chocolate from scorching.
*If using gold leaf, ensure it is labelled “edible”, “food grade safe”, and/or “24 karat”. Apply in an area away from any sources of wind. Edible gold leaf can be applied before or after slicing the bars. The surface can be completely covered with gold leaf or partially covered. With a small pastry brush, slightly dampen with water only the area to which you plan to apply gold leaf, as water will “stain” chocolate (turn the wet areas cloudy). If using loose leaf, lift carefully by the corners and lay the gold leaf, using a brush to press down. For transfer sheets, carefully lay the gold leaf, using the sheet the gold leaf is laying on to help you apply it to the dampened surface. Gently press the sheet onto the surface with your fingers before carefully peeling away the paper. Repeat procedure over the surface of the chocolate. If there are small areas that need to be covered, carefully cut the gold leaf (still attached to the sheet) into the desired size before applying. Alternatively, one can use edible gold flakes instead of sheets. Lightly brush a damp brush onto the areas that you want gilded. Sprinkle the gold flakes onto those areas. With a dry pastry brush, gently brush away the excess gold flakes.
*Dip or run a sharp chef’s knife under hot water and dry with a clean kitchen towel between cuts to ensure clean slices.
*Bars can be frozen for up to 3 months. Wrap completely cooled and cut bars in a double layer of aluminum foil, or in plastic wrap and place into an airtight container or freezer safe bag. Thaw overnight in the fridge.