This is a terrific Cuban side dish or, as we have them, just a snack. You can serve these with rice and beans and entrees of meat or fish. Plantains are becoming more available in grocery stores and they're really tasty!
In a large skillet, melt the butter with the olive oil over medium heat; add the plantain slices and fry for about 4 minutes on each side, moving the slices with a spatula occasionally to prevent sticking.
Remove the plantains from the skillet with a slotted spoon and let drain on paper towels.
Transfer to a large, warm serving platter, sprinkle with lemon juice and salt and serve warm.
*unripeplantains are green and hard, as they ripen they turn yellow and then get mottled with dark spots; Ripe plantains are sweet and soft and are brownish-black in color and resemble overripe bananas; To ripen a plantain, keep them in a warm place until they turn yellow, then brownish-black.