Scale an ingredient
Scale each ingredient separately. Pan space, cooking time and food safety do not scale automatically.
Family
A shared meal works better when the common base and the optional parts are clear before cooking starts.
In practice
Plan one base dish, separate additions and a serving quantity for the people actually eating. Record allergies and established dietary requirements explicitly; a flexible recipe is not a substitute for them.
Use the serving calculation for shopping, then ask each person which parts need to remain separate.