Preheat oven to 300* F. You will also want to start boiling a large kettle of water. Meanwhile, whisk egg yolks and sugar in a medium bowl until thick and pale yellow (about 3 minutes).
Next, (if using) split open the vanilla bean, and scrape out the seeds. In a small saucepan, combine the vanilla seeds, vanilla bean, and heavy whipping cream. Heat over medium, and let the mixture simmer for two minutes. Remove from heat, and allow the mixture to infuse for another two minutes (infusion is not necessary if you are not using a vanilla bean). Remove the vanilla bean, and discard.
Slowly add about half a cup of the vanilla-cream mixture to the egg mixture, whisking vigorously to avoid scrambling the eggs. Once tempered, slowly whisk in the remaining vanilla-cream mixture until frothy. Add the orange liqueur, cardamom, and vanilla extract (if using).
Divide the mixture between six ramekins. Place the ramekins in a 9x13 cake pan or a deep baking sheet. Place in the oven, and immediately pour the boiling water in the pan, around the ramekins, avoiding getting any water into the actual crème brûlée. You will want the water to come up about halfway on your ramekins (this will keep the crème brûlée from becoming sweet scrambled eggs).
Bake, checking for doneness around 30 minutes. When the crème brûlée is finished, it will be jiggly, but not liquidy. This may take up to 50 minutes depending on the depth of your ramekins, but do not let the crème brûlées brown. When they are finished baking, remove the crème brûlées from the oven by sliding a large spatula under each ramekin. Let them cool at room-temperature for about 30 minutes, and then refrigerate for at least one hour.
Before serving, sprinkle each crème brûlée ramekin with 1 tablespoon of brown sugar. Using a torch, brown each crème brûlée until the sugar is melted to your desired level (I like mine very caramel-y, hence the dark brown spots). Alternatively, you can do this under a broiler in the oven, watching it very carefully and pulling it out right when the sugar melts. Serve with whipped cream and berries, if desired!