The recipe for Dinner is given to you by the Merchant after doing a few quests for him.
The recipe is:
Dinner = 1x Snack + 1x Meal + 1x Dessert
Easiest way to get this one is to use the Dinner recipe at the Cooking Table and mix these three ingredients (all gold star quality):
Onion Rings (buy from Horadric the tavern keeper or talk to him while having a bronze star onion in your inventory to get the recipe)
Burger (unlocked automatically very early in-game)
Cake (Exchange 5x Honey to get the recipe from Dig the hobo)
You can technically buy the onion rings and just use a silver onion to craft a silver burger and when you mix those two with a gold cake you'll still have a 97% chance to get a gold star Dinner. Just save and reload if you somehow don't get a gold.