Stir constantly at the bottom corners to avoid scorched milk solids.
A true butter-shortbread base supports a cooked milk caramel and a thin salted dark-chocolate layer.
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Salted Millionaire Christmas Shortbread Bars Recipe
Follow the tray sizes, portions and baking intervals in the instructions below.
Total time includes hands-on preparation, required chilling or resting, whole-batch cooking, cooling and finishing.
Kitchen tools you’ll need
- 8-inch square metal pan
- parchment
- mixer
- heavy saucepan
- silicone spatula
- digital candy thermometer
- microwave-safe bowl
- sharp knife
Ingredients
US measures are approximate. Gram weights help keep portions consistent; spice weights vary with density.
Instructions
Prepare and mix
- Prepare and mix: Heat oven to 350°F (175°C) conventional or 325°F (165°C) fan. Line an 8-inch square metal pan with a parchment sling. Beat base butter and powdered sugar briefly; stir in flour and fine salt, then press evenly into the pan and prick lightly.
Bake the base
- Bake the base: Bake the single pan for 22–27 minutes until edges and surface are pale golden; whole-batch oven baking is 27 minutes. Cool 20 minutes in the pan before making caramel.
Cook the caramel
- Cook the caramel: In a heavy saucepan combine caramel butter, brown sugar, condensed milk and golden syrup. Stir over low heat until smooth, then bring to a gentle bubbling simmer and cook 8–12 minutes, stirring continuously into the corners, until thick and light caramel-colored and a probe reads 235°F (113°C). Spread immediately over the base. Caramel cooking is hands-on time, not included in the oven bake field.
Set and top
- Set and top: Cool caramel for 30 minutes, then refrigerate 60 minutes until firm. Melt chocolate and oil in 20-second microwave bursts, stirring. Spread thinly over caramel and sprinkle flaky salt. Refrigerate 30 minutes to set.
Cut and serve
- Cut and serve: Let the chilled slab stand 10 minutes, lift out and cut a 4 x 4 grid with a warmed, wiped-dry knife for exactly 16 bars. Cooling field includes 20 + 30 + 10 minutes; chill includes 60 + 30 minutes. Plan stages sequentially; butter starts softened, and allow extra time if it needs warming. Scale ingredient weights, not pan-layer thickness or oven temperature.
Chef’s Science & Pro Tips
Ingredient science
Cooking the condensed-milk caramel to 235°F gives a sliceable layer; a brief warm-up alone leaves it runny.
Technique & texture
Stir constantly at the bottom corners to avoid scorched milk solids.
Finishing & serving
Add a little oil to the chocolate so the chilled topping cuts more cleanly without needing tempering.
Storage and make-ahead
| Method | How long | What to do |
|---|---|---|
| Room temperature | 2 hours | Up to 2 hours for serving. Serve filled bars in small batches; return to the refrigerator promptly. Reduce to 1 hour if the room is above 90°F (32°C). |
| Refrigeration | 4 days | Up to 4 days. Keep filled bars airtight at 40°F (4°C) or below. Plain shortbread needs no refrigeration; the assembled filling is why this recipe specifies chilled storage. Separate layers with parchment. |
| Raw freezing | 1 month | Up to 1 month, dough only. Freeze only the shortbread dough, well wrapped; thaw covered overnight in the refrigerator, then shape and complete the recipe's full bake. Make fillings fresh; do not freeze raw egg custard or raw frangipane in assembled bars. |
| Baked freezing | 1 month | Up to 1 month. Freeze fully cooled filled bars airtight between parchment layers. For sandwiches, freezing unfilled baked halves and adding fresh filling gives a crisper crumb. Thaw filled items covered overnight in the refrigerator. |
| Restoring | 2 hours | Overnight refrigerated thaw; 10–20 minutes before serving. Thaw filled items covered in the refrigerator. Let a serving portion stand 10–20 minutes to soften, keeping the total room-temperature exposure within 2 hours. Do not oven-reheat filled items; add fresh powdered sugar or cocoa after thawing where used. |
Notes
- Scale ingredients, including US measures, without changing cookie size or oven temperature. Extra trays increase whole-batch time.
Nutrition
Approximate values per portion from the listed ingredient weights divided into 16 equal portions. Includes required fillings and finishes. Brands, unused coatings and actual portion size affect the estimate.
Frequently Asked Questions
Is the caramel saucepan time included in bake?
No; the bake field is the 27-minute whole-pan oven bake. The 8–12 minutes of stirred caramel cooking are included in active time.
Why can't I use caramel sauce?
A pourable sauce will not make the firm layer required for the 16 bars.
Why does the chocolate crack on slicing?
Very cold chocolate is brittle; use the 10-minute stand and a warmed dry knife with gentle downward cuts.
