A 3-tier egg cooker/vegetable steamer is a compact kitchen appliance with stacked baskets that uses steam to cook eggs and a variety of vegetables simultaneously, offering a healthy and efficient way to prepare meals. Key features typically include a water reservoir for steam generation, an adjustable timer, multiple trays for holding food, a BPA-free design for safety, and a steam vent lid for controlled cooking. Some models allow for up to 16 eggs and a large capacity for vegetables, while others offer features like auto shut-off and energy-saving capabilities.