Martha Kostyra Martha Stewart’s "greatest teacher" was her mother, Martha Kostyra, affectionately known as Big Martha. At their family home in Nutley, N.J., Mrs. Kostyra instilled a love of cooking, along with housekeeping skills and a drive for hard work and self-sufficiency. Over the years, Mrs. Kostyra was a frequent guest on Martha’s TV shows, cooking alongside her daughter with authority, and often sharing cherished family recipes. Her most-loved recipe is for a simple side dish, Big Martha’s Mashed Potatoes, a legendary recipe rich with cream cheese. About Martha Stewart Martha Stewart, a Dotdash Meredith Brand, teaches and inspires over 7 million readers a month with tested-until-perfected recipes, elevated home and entertaining ideas, and creative DIY projects. Our content is written by experienced journalists and fact checked for accuracy. Learn more about us and our editorial guidelines.