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

To make the Salted Caramel:

Combine all the caramel ingredients in a small saucepan over medium-high heat. Stir gently for the first minute. Once the mixture starts to heat and you notice wisps of steam, begin whisking continuously—but gently—for about 7 minutes, being careful not to let it catch or burn at the bottom (see Note 3). The mixture should turn a light golden color. Take it off the heat and continue whisking for another 30 seconds. Cover the pan with a lid and set the caramel aside, keeping it warm and pourable.

For the Brownies:

Melt the chocolate and butter: Place both ingredients in a microwave-safe bowl. Heat in 30-second intervals on high, stirring after each round, until the mixture is smooth and fully melted.

Mix in the wet ingredients: Stir in the brown sugar, whisked eggs, and vanilla extract until everything is well incorporated.

Add the dry ingredients: Sift the flour, cocoa powder, and salt directly into the bowl. Gently fold everything together until you get a smooth, even batter.

Assemble the brownie layers:

Scoop out ½ cup of the brownie batter and set it aside. Pour the rest of the batter into the lined baking pan and spread it evenly across the bottom.

Add the caramel layer: Carefully pour the warm salted caramel over the brownie batter. Try to cover as much surface as possible, since spreading the caramel after pouring is difficult. If the caramel has cooled and thickened, warm it briefly on the stove for about a minute to make it pourable again.

Top with remaining batter: Drop spoonfuls of the reserved brownie batter randomly over the caramel. Use a knife or skewer to swirl the batter—this won’t be very visible after baking, but it helps to spread the top layer over the caramel.

Bake the brownies:

Transfer the pan to the preheated oven and bake for 30 minutes if you want very gooey brownies, or up to 35 minutes for a firmer, yet still moist texture.

Cool before slicing: Let the brownies rest in the pan for 10 minutes. Then, using the parchment paper overhang, lift them out and place on a wire rack. Allow them to cool for another 20 minutes before cutting into squares. Keep in mind that the caramel will be soft while warm but will firm up as it cools, allowing for cleaner slices.