By Tim Jimenez, Erika Von Tiehl

PHILADELPHIA (CBS) — Today is National Grilled Cheese Day, and many restaurants are taking the sandwich that mom used to make to a whole new level.

READ MORE: Nationals GM Mike Rizzo Calls Phillies Manager Girardi A 'Con Artist'

There are even restaurants dedicated to grilled cheese, including one at the Reading Terminal Market called “Melt Kraft.”

Chef and manager Rebecca Foxman (photo) calls this day her favorite day of the year — about a sandwich close to her heart.

“It’s a nostalgic and very classic sandwich, and many people have a really firm idea of what makes a really good grilled cheese,” she tells KYW Newsradio.

READ MORE: 11-Foot-Long Great White Named Freya Spotted Off Coast Of Jersey Shore Last Week

But many eateries, Melt Kraft among them, aren’t just using butter, bread, and cheese.  They strive for fresh and unique ingredients.

Foxman has one called the “Valley Thunder” sandwich:

“It’s farmhouse, cloth-bound cheddar with our own homemade, braised, Jewish-style brisket, a little bit of our day-old mozzarella that we make fresh in-house every day, and then it has a layer of macaroni and cheese on top.”

And there may be no better side dish, of course, than a warm bowl of tomato soup, perfect on this rainy National Grilled Cheese Day!

MORE NEWS: Philadelphia Union to Have Full Stadium At Subaru Park For First Time Since October 2019