In a deep fryer or large skillet, heat the oil over moderate heat to 350ºF.
With a sharp knife, cut the ends from each plantain and score the skins lengthwise several times to peel away the skin. Cut the plantains into 1 1/2- inch thick slices. In batches, fry the plantain pieces until just golden, about 2 minutes per side. Transfer with tongs to paper towels to drain.
Place a plantain slice on a flat work surface, and press down on it firmly with the back of a heavy plate or skillet until flattened to about 1/4-inch thick. Repeat with the remaining slices.
Reheat the oil and fry the tostones to a deeper color and warmed through, about 1 minute. Drain on paper towels and season with salt and Essence. Serve hot.
Yield: Makes 20 – 24, or 4 – 6 servings