5 ounces mexican chocolate such as ibarra or abuelita*, or good-quality semi-sweet chocolate, chopped into small pieces (about 1 heaping cup)
1 teaspoon vanilla or almond extract
1 teaspoon cinnamon
1/8 teaspoon cayenne pepper
1/3 cup sugar
5 large egg yolks
1 cup sliced almonds
in a medium saucepan, combine half of the half and half with the cocoa powder and simmer over medium-low heat for about a minute, stirring with a whisk until all the cocoa lumps are broken up. remove from heat and add chopped chocolate, stirring until pieces are melted. stir in vanilla or almond extract, cinnamon and cayenne pepper. set aside.
once milk mixture is hot, remove from heat and slowly pour into egg mixture, whisking constantly. pour milk and egg mixture back into the saucepan and cook, stirring constantly, over low heat until it registers 170°f on thermometer and a finger drawn across the back of the custard-covered wooden spoon leaves a mark.
remove from heat and pour through a fine-meshed sieve into a large heat-proof bowl. pour in chocolate mixture, scraping with a spatula to get ever last bit. whisk until custard is smooth. stir in sliced almonds. set bowl over ice water bath to chill for 15 minutes.
once ice cream base is cold, cover and place in the refrigerator to chill completely, at least 3 hours or overnight. once chilled, freeze in an ice-cream maker according to the manufacturer’s instructions.