In a large skillet heat the butter until it melts over medium high heat. Add the corn, season with salt and pepper and sauté for 5 minutes, not stirring too much, until the corn is browned in places, and cooked. Transfer to a bowl and cool.

Add the tomatoes, onions and scallions to the bowl. In a small bowl or container combine the olive oil, sour cream, lime juice, chili powder and salt and pepper. Pour over the salad, and toss. The salad can sit for a couple of hours, covered. Just before serving add the bacon and cilantro and toss again. Serve at room temperature.