@Jennifer976 . General rule of thumb is your actual cost of food multiplied by three. Minimum. So you would need to calculate how much that salmon dinner will cost in ingredients, based on a fixed portion size, and then price it from there. BTW, hearty and healthy are not mutually exclusive!
Other funny things to consider is, WHEN do they have to tell you if they are opting in. Nothing would be more frustrating than thinking you were only serving two people and it turned out to be fie after you had done your shopping.