First Step: Preheat your oven to 350°F and line an 8×8 or 9×9 inch pan with parchment paper, leaving a 2-inch overhang for easy removal. Measure out all ingredients, ensuring cream cheese and egg are at room temperature for smooth mixing tip: let them sit for 30 minutes to avoid lumps. For vegan adaptations, have plant-based substitutes ready, like vegan cream cheese, to maintain the creamy texture in your Millionaire Shortbread Cheesecake Bars.

Second Step: In a bowl, mix all-purpose flour, brown sugar, and salt until combined, then work in the softened unsalted butter with your fingertips until the mixture is crumbly. Press this evenly into the prepared pan and bake for 10-12 minutes until golden watch closely to prevent over-browning. If making gluten-free Millionaire Shortbread Cheesecake Bars, use gluten-free flour and extend bake time by 2 minutes if needed for a firm base.

Third Step: Reduce the oven temperature to 300°F, then beat the softened brick cream cheese until smooth, about 2 minutes on medium speed. Add brown sugar and vanilla extract, beating until glossy, then mix in 1 large egg until just combined to avoid over-mixing and potential cracking for low-calorie versions, use a sugar substitute here. Gently incorporate the salted caramel sauce and sour cream, ensuring everything blends without air pockets, which could affect the set of your caramel shortbread bars.

Fourth Step: Pour the cheesecake filling over the baked crust, spreading it evenly. Bake for 22-26 minutes until the edges are set and golden, with a gentle wobble in the center if it’s for a vegan version, check at 20 minutes as plant-based fillings may set faster. Let it cool completely on a wire rack, then refrigerate for at least 2 hours to firm up, troubleshooting any runniness by ensuring the egg is fully incorporated.

Fifth Step: Heat heavy whipping cream and optional corn syrup until simmering, then pour over finely chopped dark chocolate and stir until glossy and smooth. Spread this ganache over the chilled cheesecake layer, add dollops of salted caramel, and swirl gently with a toothpick for that signature look. For low-calorie adaptations, use dark chocolate with higher cocoa content to reduce sweetness without altering the texture of your Millionaire Shortbread Cheesecake Bars.

Final Step: Chill the assembled bars for at least 2 hours, or overnight for best results, to ensure clean slices use a hot, dry knife for cutting, wiping between slices to prevent sticking. Garnish with flaky sea salt and serve as is, or with fresh berries for added appeal; for meal prep, store portions in the fridge and note that vegan versions might need extra chilling to hold shape.