As with any product, YOU have to decide what YOU want as a profit margin and if the customer wants to pay that, then you're golden.
If you want a 75% gross profit on the food (NOT NET profit) then multiply your food COST by four and you'll have a 25% COS.
Hypothetically, let's say a pan of Mac&Cheese cost you $10 to prepare. Sell it for $40 ($10/$40=25%). You'll get a $30 GROSS profit. BUT, remember... GROSS profit has to pay all other expenses; YOU have to decide if your labor, time, materials (ie pans, lids etc), insurance, taxes, fuel, and on and on is worth $30 profit per pan of Mac&Cheese. If that works for you, great.
In my more controlled world of managing a $2,000,000 food and beverage operation at a private country club, when someone asks me "how much" for a menu, I have the chef pre-cost the menu and I divide the cost estimate by 40% and that's what I quote the client (ie Hors d'oeuvres, soup/salad, protein, starch, vegetable, breads, butter, dessert estimated to COST us $15.00 pp.... I divide $15.00 by 40% = $37.50 pp for the menu and I have a 40% COS). Unlike you, I have other revenue streams to cover labor, time, supplies, insurance, lights, taxes, fuel, etc. and unlike you, I'm a "Not-For-Profit" operation.... 40% COS is way high for a profit seeking business IMHO.
Good luck. Hope this helps.
