Step 1Crush the espresso beans and cardamom by placing them together in a thick plastic bag and lightly pounding them or crushing them with something heavy (a rolling pin or wooden mallet works well). The espresso beans should have the texture of coarsely chopped nuts, and the cardamom pods should split open.
Step 2In a medium saucepan, bring the cream, milk and crushed espresso and cardamom to a boil. Remove the saucepan from the heat. Cover the mixture and let the coffee and cardamom steep in the cream for about 1 hour.
Step 3Heat the oven to 300 degrees.
Step 4In a small bowl, whisk the egg yolks and sugar together until thoroughly combined. Strain the cream (which is now infused with cardamom and coffee) through a fine sieve into the yolks, while whisking.
Step 5When combined, strain again through the fine sieve to remove any pieces of cooked or lumpy yolk. Stir in the brewed espresso and espresso grounds.
Step 6Fill eight espresso cups or ramekins with the mixture, pouring almost to the top, and place the cups in a large oven-proof baking dish. Pour lukewarm water into the baking dish until it reaches halfway up the sides of the cups or ramekins. Using a small spoon, skim any fine bubbles that form on the top of each custard. This will ensure a smooth and creamy top.
Step 7Cover the pan tightly with foil and bake for 50 to 55 minutes. Carefully remove the foil, because escaping steam can burn fingers. Test for doneness by shaking the pan gently; the cremes should be set around the edges and not quite firm in the center. Remove the cremes immediately from the pan and set them onto a baking sheet or tray, allowing them to cool for 5 to 10 minutes.
Step 8Refrigerate the cremes for several hours to chill and set. Top with whipped cream beaten to soft peaks and serve.