The two main ingredients needed to make a meringue are egg whites and sugar. Egg whites provide the structure and volume, while sugar stabilizes the mixture and adds sweetness. To create meringue, egg whites are beaten until they reach stiff peaks, indicating that air has been incorporated, making the mixture light and fluffy. Gradually adding sugar during the beating process ensures that it dissolves properly, resulting in a glossy finish. Meringue can be used for various desserts, including pavlova, meringue cookies, and as a topping for pies.