Preheat oven to 325 F

Line an 8×8 square baking pan with parchment paper and coat the paper in butter (if you leave some hanging over the edges, it makes it really easy to lift the brownies out of the pan!).

In a double broiler, saucepan, or the microwave, melt the chocolate and butter. Stir it often so it does not burn.

Pour the melted chocolate/butter into a large bowl.

Whisk in the sugar, salt and vanilla.

Add the eggs one at a time, whisking to combine each addition.

Sift the cocoa powder over the chocolate and stir to combine.

Add the starter and stir gently until it is completely incorporated and you don’t see any streaks of starter.

Place the batter into the prepared pan evenly and bake for about 30-40 minutes, or until a toothpick inserted into the center comes out clean.

Cool in the pan 20 minutes (this is the hardest part), lift the parchment paper out and allow to cool the rest of the way on a wire rack.

When cool completely, cut into squares and enjoy!