With a vegetable peeler cut the carrot, the zucchini, and the yellow squash lengthwise into "ribbons," reserving the center cores for another use. In a glass dish microwave the vegetables, covered, at high power (100%) for 2 minutes, or until they are crisp-tender. In a small glass dish or glass cup combine the butter, the horseradish, and the lemon juice and microwave the mixture at high power (100%) for 20 seconds, or until the butter is melted. Pour the horseradish butter over the vegetables, season the vegetables with salt and pepper, and toss them well.
