Digby makes use of ingredients including flowers, vegetables, meats, herbs, spices, alcohol, fruits and berries, eggs, milk, grains, and honey.

Foreign influence can be seen in recipes such as "Pan Cotto, as the Cardinals use in Rome", and "A savoury and nourishing boiled, Del Conte di Trino, a Milano," which calls for costly ambergris, dates, raisins, currants and sugar; the bird is boiled inside an ox bladder.

Advice is given that diverges from the recipe headings onto related topics. In "Tea with Eggs", it is advised not to let tea soak too long in hot water "which makes it extract into itself the earthy parts of the herb", but "The water is to remain upon it no longer then whiles you can say the Miserere Psalm very leisurely.

Thus you have only the spiritual parts of the Tea". Similarly under "Pan Cotto", the author gives general advice upon breakfasting, recommending "juyce of Orange", cream of oatmeal or barley, and ending "Two poched eggs with a few fine dry-fryed Collops of pure Bacon, are not bad for breakfast, or to begin a meal".

Instructions are given "to feed Chickens" and other poultry.

The Closet Opened begins with a section on brewing soft and alcoholic drinks. There are many recipes for mead and metheglin, and some for ale, cider, and wines from fruits including cherry and strawberry.It then provides recipes for "sallets", eggs, potage, meat pie and meat and vegetable pasties, cooked and prepared meats, syllabub, cakes, pies, puddings and other desserts.