Buongiorno on this glum Thursday.

Say cheese.

The Feast of San Gennaro returns to Little Italy today, leaving Mulberry Street dazzling in red, white and green for nearly two weeks.

And smelling mouth-wateringly wonderful.

Now that we (hopefully) have you daydreaming about pizza — perhaps before you’ve even had breakfast — allow us to further whet your appetite with a lesson on our city’s signature food.

“New York pizza is all relatively thin crust without being crackery,” according to the pizza historian Scott Wiener. “It has a risen edge — a little bit of a handlebar, not a thin, flat edge — baked at about 550 degrees in a deck oven.”

Mr. Wiener, who leads pizza tours of New York restaurants and wrote the book “Viva La Pizza! The Art of the Pizza Box,” labeled our city a “slice town,” distinct from places that put more emphasis on an entire pie.