Step 1In the top of a double boiler, combine the egg yolks and evaporated milk. Cook over lightly simmering water, stirring constantly, until the mixture is thick enough to coat the back of a spoon, about 5 minutes.
Step 2Transfer the mixture to a blender. Add the cream of coconut, sweetened condensed milk, rum, water, cloves, allspice, nutmet, cinnamon and vanilla, and blend for about 30 seconds. Pour into a glass bottle and chill overnight.
Step 3Fill 10 wine glasses with ice, and add 6 ounces coquito to each. Top with freshly grated nutmeg and semisweet chocolate.