Step 1

Preheat the oven to 300° F. Lightly brush eight 3-inch ramekins with melted butter and place in a large roasting pan.

Step 2

Heat the combined cream and milk in the microwave to piping hot, about 1 1/2 minutes. Add the chocolate, cocoa powder, espresso powder, and cinnamon to the hot milk. Whisk until the chocolate is completely melted into the liquid. (You may need to heat the mixture for an additional 30 to 45 seconds to encourage the chocolate to melt.) Let the mixture cool to room temperature.

Step 3

In a separate bowl, whisk the eggs and yolks until slightly thickened. When well-blended, stir in the cream/chocolate mixture, Kahlua, sugar, vanilla, and salt. Pour this mixture into the prepared ramekins.

Step 4

Carefully pour enough hot water into the roasting pan to reach halfway up the sides of the ramekins. Bake for about 30 minutes, until barely set when you gently jiggle them (it will still look runny in the middle).

Step 5

Remove the roasting pan from the oven and let cool. When cool, remove the ramekins from the pan, tightly cover each ramekin with plastic wrap, and refrigerate at least 2 hours or up to 2 days. The custard will remain slightly soft in the center, even when cool.

Step 6

To finish: Preheat the broiler and place a rack as close to the flame as possible.

Step 7

Use a fork to toss the granulated sugar lightly with the orange zest. Sprinkle an even layer across each custard to cover completely, about 1 tablespoon each.

Step 8

Place the sugared ramekins on a baking sheet and place under the broiler until the sugar caramelizes and bubbles, about 2 to 4 minutes. Depending on your broiler, you may need to rotate them with tongs to color evenly. Remove the ramekins from the oven and let cool. The sugar top will harden. The crèmes may be served immediately. However, I prefer them chilled for at least an hour and no more than three (or the sugar crust will begin to weep).