Making the batter: Place a double boiler over medium heat. Add the dark chocolate and butter to the top pan and stir until the chocolate has melted. Once melted, remove the pan from the heat and let the chocolate cool slightly. Whisk in the brown sugar and eggs. With a wooden spoon, fold in the walnuts, flour and sea salt.
Making the goat cheese mixture: In a large mixing bowl, combine the goat cheese, brown sugar and egg. Blend using an electric beater set to low speed.
Preheat the oven to 325 degrees F.
Making the brownies: Line a baking dish with parchment paper and grease with the butter. Pour the brownie batter into the baking dish, then evenly scatter spoonfuls of the goat cheese mixture over the batter. With a knife, score the surface into a pattern.
Bake the brownies for 40 minutes. When done, remove to a wire rack to cool. Once cool, cut the brownies into bars, remove them from the baking pan and refrigerate.