Recipes are unique combinations of ingredients using the drinks, desserts and toppings you have unlocked so far in the game. As you level up, you can make additional recipes once you purchase the newest equipment available for your level.
Customers will start asking for recipes using your current level's equipment even if you have not purchased the equipment or unlocked the recipes yet. They will leave your café if you do not serve them unless they are ordering something else in addition, but they will return to your café later. In your café's profit summary, a negative amount may be shown from customers whose orders your staff were unable to complete while you were away from the game, either due to lacking the required equipment or the recipe being locked.