Feed a family

I have a family of three: myself, my 14-yr-old tall and thin son, and my 51-yr-old tall and thin husband. They will eat whatever I cook, so I figured I could just multiply the recipes to cook for 3. I cannot figure out how to do this in the menu or the grocery list. When it gives me the option to number my servings (I’ve already clicked on the option to include the recipes in the list), I only get two items: pizza toppings and free spread. The options for those are locked at 1 and 3, respectively. How do I create a list so I can shop for 3 people?