3 to 4 large unripe (green) or barely ripe (slightly yellow) plantains
about 2 cups olive, canola, or peanut oil for frying
1. With a sharp small knife cut ends from each plantain and cut a lengthwise slit through skin. Cut plantains crosswise into 1-inch-thick pieces and, beginning at slit, pry skin from pieces. (Warning: this is a little trickier than peeling bananas!)
2. In a 12" nonstick skillet heat 1/2 inch oil over moderate heat until just hot enough to sizzle when a plantain piece is added. Fry plantains in batches, without crowding, until tender and just golden, 2 to 3 minutes on each side. With tongs transfer plantains as fried to paper towels to drain.
3. Remove skillet from heat and reserve oil. With the bottom of a heavy saucepan or a wide solid metal spatula flatten plantains to 1/4 inch thick (about 3 inches in diameter). This is the most fun part.
4. Dip flattened plantains into a bowl of warm salted water, 1 at a time. Heat reserved oil over moderate heat until hot but not smoking and fry flattened plantains in batches, without crowding, until golden, about 3 minutes. Use tongs to transfer tostones to paper towels to drain. Season with salt if desired.
5. Serve immediately.
Yield: Makes 18 to 24 tostones