The Bits and Bobs:
5 oz. good quality, dark, unsweetened chocolate, chopped
1 cup unsalted butter
1/4 cup unsweetened cocoa powder
2 cups sugar
1/2 tsp vanilla extract
1/4 tsp salt
1 1/4 cups all-purpose flour
Over a simmering water bath, melt the butter and chopped dark chocolate together, stirring every once and awhile until completely smooth. Remove from heat and whisk in the cocoa powder. Allow to cool slightly.
Preheat the oven to 350°F and grease a 9x13-inch pan with a little butter.
Once the chocolate has cooled a bit, whisk in the sugar until some of the grit of the sugar has melted down. Whisk in the eggs one at a time and then the vanilla extract. Working in two batches, fold in the flour and salt. If you are adding any mix-ins, add those now. Fruit will have to be worked in with care to try and keep some of the fruit in tact (a little fruit puree is ok). Stir until just combined. The batter will be very thick.
Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted comes out clean.