Martha Stewart is expanding her home line into a new category. Instagram/Martha Stewart; Instagram/Amazon Home Martha Stewart is always cooking up something new. The domestic doyenne expanded her business empire again this week, dropping her first-ever countertop appliances collection — and it starts at just $50 on Amazon. Stewart told People the new range features “impeccably designed” machines, combining functionality with “timeless, thoughtful designs to enhance one’s everyday culinary experiences.” Her favorites include the French Door Air Fryer Toaster Oven Combo , which is designed to perform 12 different cooking functions all in one — including baking, broiling, roasting and even cooking up to a 12-inch pizza.…