For sauce, in a small saucepan cook onion in butter over medium heat for 3 to 4 minutes or until tender. Add mango and wine. Bring to boiling; reduce heat. Simmer, uncovered, for 5 minutes. Cool slightly. Place mixture in a food processor bowl or blender container; cover and process or blend until smooth. Add hot pepper sauce to taste. Cool to room temperature.

In large saucepan heat 1 inch oil over medium heat to 365 degree F. (Or, use a deep fryer set to 365 degree F.) Add plantain slices, 4 or 5 at a time, and cook for 2 to 3 minutes until lightly golden, turning them once. Remove plantains with a slotted spoon; drain on paper towels.

Transfer plantains to a cutting board or work surface. Flatten slices with the bottom of a heavy saucepan to 1/8-inch thickness. (If slices stick to the saucepan, use a wide metal spatula to remove.) Reheat oil if necessary. Return flattened slices, 4 or 5 at a time, to hot oil and fry for 3 to 4 minutes more or until crisp and deeply golden. Drain on paper towels and sprinkle with salt. Serve tostones warm with dipping sauce. Makes 4 servings.

Trim off ends and cut a few slits in skin from end to end. Push thumb under skin and peel it off in sections.