Preheat oven to 300°F Bring cream and milk to boil in heavy large saucepan. (This would be when to add the cayenne and cinnamon if you're making the Aztec Creme Brulee) Reduce heat to low. Add chocolate and whisk until melted and smooth. Remove from heat. Whisk yolks and 1/3 cup sugar in large bowl to blend. Gradually whisk in hot chocolate mixture. Strain.
Divide custard among 10 6 oz custard cups. Place cups in large baking pan. Add enough hot water to pan to come halfway up sides of cups. Bake until custards are set, about 50 minutes. Remove from water; chill 2 hours. Cover and refrigerate overnight.
Preheat broiler. Sprinkle each custard with 1 tablespoon sugar. Broil until sugar turns golden, watching closely to avoid burning, about 3 minutes.