Preheat oven to 350F. Butter 6 (5-ounce) ramekins and place in a baking dish with high sides. Heat some water in a kettle or in a pot on the stovetop - you'll be partially filling the baking dish with hot water just before baking the cakes to make a bain marie.

Beat the butter and sugar together in a large mixing bowl until light and fluffy and fully combined.

Add the egg yolks, one at a time, allowing each one to get fully incorporated before adding the next.

Whisk together the flour, cinnamon, cloves, ginger, and cardamom, and fold that into the mixture.

Add the buttermilk and the canned pumpkin, and continue to mix until smooth and fully combined.

In a stand mixer with a whisk attachment, or with clean electric beaters, whip the egg whites and the cream of tartar until stiff peaks form.

Gently fold the egg whites into the pumpkin mixture until no large lumps or streaks of whipped egg white remain.

Spoon the batter into the prepared ramekins, filling them almost to the top.

Add the hot water to the baking dish with the ramekins, you want the water to reach about half way up the sides of the ramekins. Note: It may be easiest to add the water to the pan once you've already placed it on your baking rack in the oven - that way you don't have to transfer the dish with the water and the ramekins in it.

Bake for about 45 minutes until puffed up and golden, and not wobbly in the middle.

Remove the ramekins from the water bath and set aside to cool. They will sink slightly.

In a skillet, toast the pecans with the sugar over medium heat until the pecans are toasted and the sugar melts and coats the pecans. Watch them carefully so they don't burn. Remove from the pan and allow to cool. They will get crunchier as they cool.

Whip the heavy cream and the confectioner's sugar until soft peaks form. You can also leave the cream unsweetened, which is how I often do it.

Add a dollop of whipped cream to the top of the pumpkin cakes (you can eat them warm or cooled), and top with the candied pecans.