Fill a small or medium saucepan a quarter way with water. Bring this to a boil then a gentle simmer on low.

In a glass or stainless steel heat proof bowl whisk together the eggs. Place the bowl over the simmering water so it’s sitting on top of the saucepan but the bowl should not be touching the water. Whisk the heavy cream and lime zest in with the eggs and keep whisking for about 3 minutes. This is to temper the eggs. You have to keep whisking so the eggs do not become scrambled eggs.

After the 3 minutes have passed, strain this mixture into a blender or large mixing bowl. Add the evaporated milk, condensed milk, bitters, nutmeg, cinnamon, vanilla extract and puncheon rum. Mix this together until smooth and incorporated.

Store in an airtight container or bottle and refrigerate. It will last in the fridge 2-4 weeks.