Agnes Marshall designed and patented various ice cream-making machines, aimed at simplifying and improving the process. These inventions reflected her commitment to technological innovation in the kitchen.

Agnes Marshall was a pioneer in the use of liquid nitrogen for freezing foods. She described it as a method for rapid freezing in some of her books, and lectured about it in some of her courses, long before it became a popular method of quick freezing in modern molecular gastronomy.

Agnes Marshall was known for her willingness to experiment with new cooking techniques and ingredients. Her innovative approach pushed the boundaries of culinary possibilities.