• Preheat your oven to 180°C (350°F), suitable for all oven types. Grease a 20cm (8-inch) square baking tin with butter, then line it with parchment or baking paper to ensure easy removal later.

Salted Caramel:

• In a small saucepan over medium-high heat, combine all the caramel ingredients. Stir occasionally during the first minute. Once the mixture begins to heat and you see light wisps of steam, start whisking continuously—but gently—for about 7 minutes, making sure to prevent the mixture from catching or burning on the bottom of the pan (see Note 3). The caramel should turn a light golden color. Remove it from the heat and continue whisking for an additional 30 seconds. Cover with a lid and set aside, keeping it warm and pourable.

Brownie Batter:

• To begin, melt the butter and chocolate together. Place them in a microwave-safe bowl and heat in three 30-second intervals on high, stirring well after each burst, until the mixture is completely melted and smooth.
• Next, stir in the brown sugar, whisked eggs, and vanilla extract. Mix until fully combined.
• Sift in the flour, cocoa powder, and salt directly into the bowl. Mix gently until you have a smooth, cohesive batter.

Assemble:

• Scoop out ½ cup of the brownie batter and set it aside. Pour the rest of the batter into your prepared baking tin, spreading it evenly.
• Next, carefully pour the warm salted caramel over the brownie layer. Try to cover the surface evenly, as spreading the caramel afterward can be tricky. If the caramel has thickened or cooled too much, reheat it briefly on the stove for about a minute to loosen it.
• Then, spoon the reserved brownie batter over the caramel in small dollops. Using a knife or skewer, create swirling patterns—while these swirls might not be very visible once baked, this step helps to distribute the brownie layer over the caramel.

Bake:

• Place the tin in the preheated oven and bake for 30 minutes if you prefer a gooey, molten center, or up to 35 minutes for a firmer, still moist texture.
• Once done, allow the brownies to cool in the pan for 10 minutes. Then, lift them out using the overhanging paper and place them on a wire rack to cool for another 20 minutes before slicing. Keep in mind that the caramel may still be soft when warm but will firm up as it cools, allowing for neat, clean cuts.