CARAMEL LAYER

1. Grease and line an 8" (20cm) square pan with parchment paper, leaving the parchment extending over the sides of the pan to form a sling to remove the caramel with later. Secure with binder clips if desired. 
2. In a medium sized heavy bottom saucepan, combine the butter, condensed milk, brown sugar, and golden syrup. 
3. Place over medium high heat, stir until melted together, and bring to a boil. Cook, stirring constantly (I like to use a whisk then switch to a rubber spatula) until the caramel registers 240°f / 120°c on a thermometer. Watch the bottom carefully to avoid the mixture catching, turning down the heat if needed or removing the caramel from the heat, stirring well, then returning to the heat. 
4. Once the caramel has reached the correct temperature, remove from the heat, and add the salt and vanilla. Mix well to combine, then transfer to the prepared pan. Shake to evenly distribute the caramel. 
5. Chill the caramel for at least an hour, or until you can no longer feel heat in it. This step can be done up to two days in advance. 

CARAMEL BROWNIES

1. Preheat the oven to 350°f / 180°c. Grease and line a 9x13" (20x30cm) pan with parchment paper, making sure the parchment sticks up a little to allow easy removal.
2. In a heatproof bowl over a pan of simmering water (make sure the bowl does not touch the water), combine the dark chocolate and butter. Heat, stirring frequently, until the chocolate and butter are melted and the mixture is smooth. Alternatively you can do this step in the microwave - microwave for 30 second increments, stirring well after each until the mixture is smooth and combined. 
3. Sift the cocoa powder over top of the chocolate and butter mixture and stir until well combined.
4. In a large bowl, combine the eggs, granulated sugar, and brown sugar. Mix on medium to high speed with an electric handheld mixer for 2-3 minutes until the mixture has lightened and increased in volume. This step can also be done in a stand mixer using the whisk attachment.
5. Add the chocolate mixture and mix to combine. Add the salt and vanilla and mix until incorporated. 
6. Add the flour and incorporate by hand until the mixture is smooth and does not have any lumps. 
7. Transfer the batter to the prepared pan, and tap the pan on the counter a few times to ensure there are no air bubbles. Leave to sit for a minute or two then bang again to ensure there are no bubbles.
8. Remove the cooled caramel from the fridge, remove from the pan, and place onto a cutting board. Using a very sharp knife, cut the caramel into squares - I did an 8x8 grid.
9. Dot the caramel squares over the surface of the brownie - see image in the blog post for a visual reference. You may not use all of the caramel, I usually have a few pieces leftover that I store in the fridge. 
10. Press the pieces down lightly if desired, or leave sitting on top of the brownie - they will melt down slightly. 
11. Bake the brownies for 25 to 28 minutes, until they are set around the sides and a skewer or knife inserted into the middle comes out with only a few moist crumbs attached. You are better to under bake than over bake. 
12. Leave the brownies to cool at room temperature for about 30 minutes, then transfer to the fridge to allow to cool completely. Alternatively you can cool fully at room temperature. 
13. Cut into pieces using a large, sharp knife, wiping the blade between cuts. Store the brownies in an airtight container in the fridge or at room temperature - they will keep in the fridge for up to a week.