The Dish: The perfect bagel sandwich from Bart's Bagels in Bala Cynwyd, Pa.

BALA CYNWYD, Pa. (WPVI) -- In this edition of The Dish, two brothers who grew up in Bala Cynwyd, Pennsylvania, just brought the third location of their popular bagel business back to the neighborhood that raised them.

Locals and celebrities alike have become Bart's Bagels faithful, and we are headed there to learn the secrets to making the perfect bagel sandwich.

For Brett Frankel and his brother Kyle, bagels are not only culture, but they're life.

And the duo just brought their latest location of Bart's Bagels not just to their hometown, but to their home strip on Montgomery Avenue in Bala Cynwyd.

"This place used to be formerly Bravo Pizza, which is a place that we used to all come to and hang out after school," says Brett.

Bart is Brett's childhood nickname, so it all comes full circle.

"It's weird being back here 20 years later, coming into the space and having our own restaurant here now," he says.

The brothers have opened three Bart's Bagels locations in six years. First in West Philadelphia, then in South Philadelphia, and now on the Main Line.

Their bagel research goes back decades.

"I actually had a bagel every day for lunch growing up, from first grade through senior year of high school," says Brett. "I had a sandwich every single day on a bagel."

As a lifelong expert, he has a few rules for Bart's.

"The everything bagel is king," he says. "It's our number one seller across all shops. The key for me is that we don't run out of everything bagels. It's like my one big rule."

Shmears come in an array of house-made flavors, from beet horseradish to long hot to lox.

There are bagel sandwiches for every time of day, like the smoked fish diablo.

"It has pastrami, smoked salmon on it, whitefish salad that we make in-house, long hot cream cheese and pickled jalapeños," he says.

Whitefish salad is a classic Jewish deli staple, and Brett wants to keep it going strong.

"It gets the younger generation trying smoked fish," he says.

Tradition is part of the mission here.

"We do a lot of high holiday catering," he says. "We do Rosh Hashanah. We make full briskets, different potato dishes, round challahs. Yom Kippur will be a massive day for us. We will do thousands of bagels at each store."

So, here is the art of the perfect bagel sandwich, according to Bart's:

Step 1: Slice it in half, but do NOT toast it. Trust the process.

Step 2: Cream cheese goes on both sides so the stack sticks.

Step 3: Add some greens.

Step 4: For the main event, add your protein or main vegetable.

Step 5: Add a garnish if you like.

Step 6: Slice and enjoy.