In a medium saucepan, heat the granulated sugar over medium-high heat for about 5-6 minutes, stirring continuously until it turns golden brown.

Remove from heat and carefully add the cubed unsalted butter, stirring until fully incorporated.

Return to low heat and gradually pour in the room-temperature heavy cream while stirring, then add sea salt and vanilla extract, mixing until smooth. Set aside to cool slightly.

Preheat your oven to 350°F (175°C). Line an 8x8 inch baking pan with parchment paper.

In a microwave-safe bowl, melt the unsalted butter and chopped semi-sweet chocolate together, stirring every few seconds until smooth.

Stir in the granulated sugar until well incorporated.

Add in the large eggs and egg yolk, along with the vanilla extract, and mix until the batter is thick and glossy.

Sift in the all-purpose flour, cocoa powder, and salt, then fold until no streaks remain.

Pour half of the brownie batter into the prepared baking pan and spread evenly.

Drizzle the prepared salted caramel over the first layer of brownie batter and optionally swirl it gently with a knife.

Top with the remaining brownie batter, spreading it evenly to cover the caramel completely.

Bake in the preheated oven for 30-35 minutes, checking for doneness with a knife inserted in the center.

Once baked, cool in the pan, then drizzle any remaining caramel on top, sprinkle with flaky sea salt, and cut into squares for serving.