Slice plantains paper thin & place in a large bowl. Cover with water & soak for 30 minutes.
Drain slices, pat dry with paper towels. Heat oil in skillet & fry plantain slices till they are golden brown. Drain. Crush plantains in a mortar & pestle until you have a thick paste. In a large pot, heat stock & gradually stir in crushed plantain. Season well.
Simmer over low heat, stirring frequently. for 20 to 25 minutes. Serve sprinkled with lime juice.
Randelman & Schwartz, "Memories of a Cuban Kitchen"