Once you have the recipe's shortcut, you can access the settings and get the ingredients:
List<IShortcut> ingredients = recipe.Setting.GetSummedUpIngredients(combatant, true);
combatant is a Combatant instance (e.g. the player) and is used in case the ingredient quantities use something that requries a combatant (e.g. a formula for calculations). The bool value defines if chance checks are used or not, passing true uses chance checks.
The returned list of IShortcut contains all ingredients, e.g. ItemShortcut instances for items, EquipShortcut for equipment, etc.
You can get content information, quantities, etc. from those instances.