Step 1: In a high-powered blender, combine the cream of coconut, coconut milk, evaporated milk, and sweetened condensed milk. Ensure all cans are well-shaken before opening.
Step 2: Add the white rum (if using), vanilla extract, ground cinnamon, and freshly grated nutmeg to the blender.
Step 3: Blend on high speed for 2-3 minutes, or until the mixture is completely smooth and well combined. You want to ensure there are no lumps and that the consistency is uniform.
Step 4: Taste the Coquito and adjust seasonings if necessary. If you prefer more spice, add a pinch more cinnamon or nutmeg. If you want it sweeter, a tiny splash of simple syrup can be added, but typically, the condensed milk provides enough sweetness.
Step 5: Pour the blended mixture into glass bottles or an airtight pitcher. Ensure they are clean and dry for storage.
Step 6: Chill the Coquito in the refrigerator for at least 4 hours, but preferably overnight. This chilling period is crucial as it allows the flavors to fully meld and deepen, resulting in a more complex and satisfying Authentic Puerto Rican Coquito.
Step 7: Serve cold. Before serving, give the bottle a good shake to reincorporate any settled ingredients. Pour into small glasses and garnish with an extra sprinkle of cinnamon or a cinnamon stick if desired.