Beat egg and sugar with mixer at high speed for 2-3 minutes.
Meanwhile heat 1 cup heavy cream in a saucepan until warm to hot. With mixer on low pour the cream into the egg mixture slowly while mixing until combined.
Add the egg/cream mixture back into the saucepan over medium low heat and stir constantly for about five minutes until thickened slightly. Measure temperature with a thermometer and when temperature reaches 160-170° F remove from heat. Do not boil.
Stir in chocolate until melted and uniformly mixed. Cover and refrigerate for about one hour until mixture is 60-80° F after stirring to mix.
Add lilikoi butter to remaining 2 cups of cream and whip with a mixer on high speed until soft peaks form.
Remove chocolate mixture from refrigerator and fold into the whipped cream until smooth and completely mixed.
Refrigerate entire amount or divide into serving containers and refrigerate. It can be consumed immediately but will firm up a little if refrigerated. Store refrigerated for up to one week.
Makes about 8 four oz. servings.