This is the one ingredient Ina Garten refuses to buy at the store

Dedicated disciples of Ina Garten—aka all of us—are all too familiar with the Contessa's set of famed cooking commandments. And while most of us can only aspire to one day having her extensive collection of expensive Le Creuset cookware, a gaggle of friends offering freshly laid eggs and a freezer filled with homemade chicken stock, Garten always knows how to comfort us with her most famous rule of all: "Store-bought is fine."

Well, except when it comes to a certain ingredient.

In a recent interview with Time, Garten revealed the one item that doesn't pass her distinguished benchmark: pre-grated Parmesan cheese.

Related: The Barefoot Contessa throughout the years

True, we secretly might roll our eyes at her insistence on those pricey bottles of Nielsen Massey vanilla, but this is one grocery store staple we can agree with her on. Tubs of pre-grated Parmesan can often include a certain percentage of wood pulp as opposed to, you know, cheese; it can also be trickier finding a brand that actually contains authentic Parmigiano-Reggiano versus a domestic knockoff.

So if you can't fly directly to Modena to claim your own wheel of Reggiano yourself, no, store-bought is definitely not fine. (In all seriousness, a freshly grated wedge of the authentically stamped stuff, purchased from a source you trust, is your best bet.)

Related: You might want to stay away from these cheeses