Preheat the oven to 325 degrees.

Line an 8×8 cake pan or baking dish with parchment. Set aside.

Combine the chocolate, butter, half and half, and granulated sugar in a double boiler or a medium glass bowl over a saucepan of simmering water. Stir occasionally until melted and combined.

Remove from heat and allow to cool to room temperature for 15-20 minutes.

Whisk in the eggs and vanilla once cooled.

In a small bowl, combine the flour, baking soda, and salt. Stir and fold in a half cup at a time into the wet mixture.

Transfer the batter to the prepared baking pan. Bake for 50-65 minutes or until a toothpick inserted in the center comes out clean. Cover with foil if browning too much.

Cool to room temperature on a wire rack before lifting out of the pan with parchment paper and decorating.