Vagabond Pie

• 1 1/2 cup boiled and mashed sweet potatoes (or pumpkin; canned okay)
• 1 egg, beaten
• 1/4 cup sugar (or more if preferred very sweet)
• dash salt
• dash nutmeg
• 2 tbsp. butter, softened or melted
• 1 cup milk
• 1 tsp. rum