Preheat your oven to 350°F (175°C). Grease an 8-inch square baking dish and set it aside.

In a large bowl, cream together the softened butter, brown sugar, and granulated sugar until the mixture is light and fluffy.

Add the vanilla extract, sea salt, and heavy cream. Mix until combined.

Gradually fold in the flour and baking soda until a soft dough forms.

Spread the dough evenly into the prepared baking dish and smooth the top.

Bake for 25-30 minutes, or until the edges are golden and a toothpick inserted into the center comes out clean.

While the dessert is baking, prepare the salted caramel: In a saucepan over medium heat, combine the remaining sugar and a tablespoon of water. Stir until dissolved and then increase the heat, allowing it to boil without stirring until it turns a deep amber color.

Carefully add the heavy cream to the caramel and stir until smooth. Remove from heat and stir in the sea salt.

Once the dessert is out of the oven and slightly cooled, pour the warm salted caramel over the top, letting it drip down the sides.

Allow the dessert to cool completely before cutting into squares, and, if desired, sprinkle with flaky salt before serving.