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Chocolate Chip Billionaire Bars
Brownies & Bars

Chocolate Chip Billionaire Bars

Three indulgent layers, one irresistible dessert. These gluten-free Chocolate Chip Billionaire Bars combine a thick, chewy chocolate chip cookie base with a rich, buttery salted caramel layer and a smooth chocolate topping. Think millionaire’s shortbread, but with a soft chocolate chip cookie replacing the traditional shortbread. They're rich, chocolatey, slightly salty and perfect for slicing into squares.

Prep time
30–40 minutes
Cook time
35–45 minutes
Total time
3–4 hours, including cooling and chilling
Yield
One 8-inch (20cm) square tin, 12–16 bars

Why you’ll love it

  • ✓Three delicious layers of chewy chocolate chip cookie, salted caramel and smooth chocolate.
  • ✓The cookie base uses melted butter, with no mixer or chilling required.
  • ✓Made with a gluten-free 1:1 flour blend.
  • ✓Perfect for making ahead, as the layers can be prepared in stages.
  • ✓A rich, indulgent dessert that's ideal for sharing.

Equipment

  • • Kitchen scale
  • • 8-inch (20cm) square baking tin
  • • Baking paper
  • • Large mixing bowl
  • • Whisk
  • • Silicone spatula
  • • Medium heavy-bottomed saucepan
  • • Heatproof bowl
  • • Kitchen thermometer, recommended for the caramel
  • • Sharp knife

Ingredients

×1

Chocolate chip cookie base

Salted caramel layer

Chocolate topping

Method

  1. 1

    Prepare the tin. Preheat the oven to 175°C conventional / 160°C fan (350°F). Line an 8-inch (20cm) square baking tin with baking paper, leaving enough overhang to lift the finished bars out.

  2. 2

    Make the cookie dough. Melt the unsalted butter and allow it to cool slightly.

  3. 3

    Add the melted butter, light brown sugar and granulated white sugar to a large mixing bowl. Whisk until well combined.

  4. 4

    Add the whole egg, egg yolk and vanilla extract. Whisk until the mixture is smooth and glossy.

  5. 5

    Add the gluten-free flour, bicarbonate of soda and fine salt. Stir until no dry flour remains, avoiding excessive mixing.

  6. 6

    Fold through 140g of the chocolate chips or chopped chocolate, reserving the remaining 30g for the top.

  7. 7

    Leave the cookie dough to rest for 10–15 minutes to allow the gluten-free flour to absorb some of the moisture.

  8. 8

    Bake the cookie base. Transfer the dough to the prepared tin and press it into an even layer.

  9. 9

    Scatter the remaining 30g chocolate over the surface, pressing it lightly into the dough.

  10. 10

    Bake for approximately 25–30 minutes, beginning to check after 20–22 minutes. The edges should be golden and the centre set but still slightly soft. A toothpick inserted away from the chocolate should come out with moist crumbs rather than raw batter.

  11. 11

    Leave the cookie base in the tin until completely cool before adding the caramel.

  12. 12

    Make the salted caramel. Add the sweetened condensed milk, unsalted butter, light brown sugar and golden syrup to a medium heavy-bottomed saucepan.

  13. 13

    Heat over medium-low heat, stirring continuously until the butter has melted and the sugar has dissolved.

  1. 14

    Bring the mixture to a gentle, steady bubble. Continue cooking for approximately 10–15 minutes, stirring constantly and scraping the bottom and corners of the saucepan to prevent scorching.

  2. 15

    The caramel should become thick, glossy and golden, ideally reaching approximately 110–112°C on a kitchen thermometer.

  3. 16

    Remove the saucepan from the heat and stir in the vanilla extract and fine sea salt.

  4. 17

    Immediately pour the hot caramel over the completely cooled cookie base. Spread evenly to the edges using a spatula.

  5. 18

    Allow the caramel to cool slightly, then refrigerate for approximately 1 hour, or until firm enough to support the chocolate topping without the layers mixing.

  6. 19

    Make the chocolate topping. Add the dark chocolate, milk chocolate and neutral oil to a microwave-safe bowl.

  7. 20

    Microwave in 20-second intervals, stirring between each, until completely melted and smooth. Alternatively, melt gently over a bain-marie.

  8. 21

    Pour the melted chocolate over the chilled caramel layer and spread evenly using an offset spatula or the back of a spoon.

  9. 22

    Sprinkle with flaky sea salt if desired.

  10. 23

    Refrigerate for approximately 20–30 minutes, until the chocolate has set.

  11. 24

    Slice the bars. Lift the finished billionaire bars from the tin using the baking paper overhang.

  12. 25

    If the chocolate is very firm, allow the bars to stand briefly at room temperature before slicing.

  13. 26

    Use a sharp knife warmed in hot water and dried thoroughly to cut into 12–16 squares. Wipe the blade clean between cuts for neat, defined layers.

Texture notes

The chocolate chip cookie base should have golden edges with a soft, dense and chewy centre. It should hold its shape when sliced without becoming dry or crumbly. The salted caramel should be thick, buttery and slightly chewy, forming a distinct layer that holds its shape without becoming hard or brittle. The chocolate topping should be smooth and firm enough to set, while remaining soft enough to slice without shattering. The three layers should remain clearly defined, with the caramel sitting on top of the cookie base rather than soaking into it.

Serving and decorating notes

These bars are rich, so smaller portions work particularly well. A light sprinkle of flaky sea salt over the chocolate topping helps balance the sweetness of the caramel and chocolate. For the cleanest slices, allow the chocolate to set without becoming extremely cold or hard. Use a warm, dry knife and wipe the blade between cuts. Allow refrigerated bars to sit at room temperature for approximately 10–15 minutes before serving so the caramel and cookie base soften slightly.

Substitutions and variations

  • • Gluten-free flour: Use a gluten-free 1:1 baking flour blend containing xanthan gum. Different blends may absorb moisture differently and affect the finished cookie texture.
  • • Chocolate: Replace the dark and milk chocolate combination with 200g of your preferred chocolate. Using only milk chocolate will produce a sweeter topping.
  • • Golden syrup: Light corn syrup can be used at the same weight.
  • • Chocolate chips: Chopped chocolate can be used instead of chocolate chips for larger melted chocolate pockets throughout the cookie base.
  • • Sea salt: Omit the flaky sea salt topping for a sweeter finish.

Troubleshooting

  • • Cookie base is dry or crumbly: It may have been overbaked, too much flour may have been added, or the flour blend may absorb more moisture. Weigh the flour accurately and remove the cookie base once the centre is set but still slightly soft.
  • • Cookie base looks greasy: Some butter may have separated during baking. Make sure the melted butter has cooled slightly before adding the eggs and that the dough is thoroughly combined. Resting the dough before baking also allows the gluten-free flour to hydrate.
  • • Caramel is too runny: The caramel may not have cooked sufficiently. Cook until thick and glossy, ideally reaching approximately 110–112°C, before pouring it over the cookie base.
  • • Caramel is grainy: The sugar may not have dissolved completely or may have crystallised during cooking. Use gentle heat initially and stir continuously.
  • • Caramel burns or develops dark flecks: The heat may be too high or the caramel may be catching on the bottom of the saucepan. Use a heavy-bottomed saucepan over medium-low heat and stir constantly, including around the edges.
  • • Chocolate topping cracks when sliced: The chocolate may be too cold or firm. Allow the bars to soften briefly at room temperature and use a warm, dry knife.
  • • Layers mix together: The cookie base or caramel may not have cooled sufficiently before adding the next layer. Allow each layer to cool and set before continuing.

Storage

Store the billionaire bars in an airtight container in the refrigerator for up to 4–5 days. For the best texture, allow them to sit at room temperature for approximately 10–15 minutes before serving. This helps soften the caramel and chocolate chip cookie base.

Freezing

For the best results, freeze the finished bars once all three layers have completely set. Cut into individual portions and wrap securely before placing in an airtight freezer-safe container. Freeze for up to 2 months. Thaw overnight in the refrigerator, then allow the bars to sit at room temperature briefly before serving. The caramel and chocolate layers may become slightly firmer or change texture after freezing and thawing.

Safety/celiac note

Use labelled or certified gluten-free flour, chocolate, golden syrup, vanilla and other packaged ingredients where required. Check chocolate carefully for gluten-containing additions or cross-contact warnings. Prepare the bars using clean equipment, baking tins and work surfaces to prevent cross-contact. Take care when handling the caramel, as hot sugar mixtures can cause serious burns.