Preheat oven to 350˚F (175˚C).
Butter a 9x12 inch (23x30.5 cm) baking pan, fit the bottom with a piece of parchment paper and dust the inside of the pan with flour; tap the excess flour out and set aside.
Melt the chocolate in a bowl over simmering water or with a microwave oven. Remove the chocolate from the heat and let it cool slightly.
Beat the butter in a large mixing bowl with a flexible rubber spatula until smooth and creamy. Stir in the chocolate. Gradually add the eggs one at a time. Whisk and then add the sugar and ground cardamom, followed by the flour and pecans, stirring using a whisk until all the ingredients are incorporated. Do not beat or aerate.
Scrape the batter into the baking pan and smooth the top with a spatula. Bake for 20 to 25 minutes. The top of the brownies will be dry, but a knife inserted in the center will come out wet with batter on it. Transfer the pan to a cooling rack and allow the brownies to cool for 30 minutes.
Run a knife around the edges of the pan and untold the brownies. Remove the baking paper, cut the brownies, and serve.