Plantain foster with ice cream

Ingredients

• 4 tablespoons butter
• ½ cup dark brown sugar
• ¼ teaspoon cinnamon
• 1 pinch nutmeg
• 2 plantains, very ripe, sliced on bias in ½-inch (1.2 cm) slices
• ¼ cup dark rum
• ½ teaspoon vanilla
• vanilla ice cream, to serve
• dry roasted peanut, chopped, for garnish