Butter an 8x8x2 inch pan. Line with wax paper or plastic wrap. Drain pineapple reserving juice. Combine pineapple juice, rum, coconut milk – mixing well.
In a double boiler* - melt chocolate, butter, and sweetened condensed milk until smooth. Be careful not to burn. Add liquid 1 tablespoon at a time stirring after each. (more or less to your taste)
Remove from heat. Add crushed pineapple (I added only half the can.) and coconut. Pour into pan. Cool. Tip: let cool outside of the refrigerator for 30 minutes so that no condensation mars the top. Refrigerate overnight. Remove from pan. Cut into pieces. Store in a covered container.