Preheat your oven to 356°F (180°C).

Melt the butter and chocolate over a double boiler or in the microwave.

Beat eggs, sugar, and vanilla together in a mixing bowl until light and fluffy.

Allow the melted chocolate and butter mixture to cool slightly.

Add the cooled chocolate mixture to the egg and sugar mixture and mix well.

Add the flour and salt to the chocolate mixture and mix until just combined and creamy.

Grease a baking pan.

Pour the brownie batter into the greased pan.

Bake in the preheated oven for 25 minutes, or until a toothpick inserted into the center comes out with moist crumbs.

Let cool completely before cutting into squares and serving.