Q: A recipe for a spritz cookie made in a cookie press called for a cooked egg yolk. Is that a mistake?

A: It’s no mistake. Some spritz doughs use raw egg, but older, more traditional versions use cooked egg yolk. I asked Geoff Blount, the baking and pastry instructor at Central Piedmont Community College in Charlotte, N.C., to explain why.

“The answer is kind of threefold,” he said. First, eggs contain protein. Protein gives a cookie a light, airy structure. Cooking the egg beforehand keeps it from developing more protein, resulting in the denser texture that is typical of a spritz.

Second, cooking the yolk removes moisture. So the cooked yolk absorbs moisture from the dough, making a stiffer mixture that is easier to pipe and holds the pattern better.

The moisture in a raw egg also creates a little bit of steam, creating a cookie that rises a little as it bakes. That’s great for a cookie with a light texture, but not for a denser cookie like a spritz.

“The mouth-feel is more compact and creamy, like a butter cookie should be,” says Blount. “You bite in and it feels kind of crunchy, but all of a sudden, it just melts in your mouth.”