Sauce hollandaise can be lightened with whipped cream just before serving. To lighten 2 cups (500 milliliters) hollandaise, whip approximately ½ cup (125 milliliters) heavy cream. The whipped cream should be folded into the hollandaise just before serving. (If added earlier, it will release water into the sauce and the air contained in the whipped cream will be lost.) Be sure to adjust the seasoning after adding the whipped cream. This sauce is traditionally served with hot vegetables, but it also makes an excellent accompaniment for fish.