Sour Cream Limas

1 pound dried baby limas
4 cups water
¼ cup butter, melted
12 cup brown sugar
¼ cup molasses
2 Tablespoons yellow mustard
½ teaspoon salt
1 cup sour cream

Rinse beans and drain. Combine all but sour cream in crockpot. Cover and cook on low for 8 hours. Stir beans, cover again and continue cooking on low until tender. Stir in sour cream just before serving.