It started with the Pizza Al Pastor when Valentin and Eva first opened San Lucas Pizzeria in 2005.
To convince customers, he started including a sample slice with every order.
Nineteen years later, it's one of his top sellers along, with the Carnitas with pork, guajilla sauce and mozzarella cheese, and the pizza Mexicana with avocado, beans and chorizo.
San Lucas Pizzeria is named for the tiny town Valentin came from in Puebla, Mexico.
He moved to the US when he was 15 to earn money to send back to his family.
He settled first in Brooklyn and then came to Philadelphia 27 years ago.
It was here he started working in restaurants, getting his start as a very ambitious, eager-to-learn dishwasher.
His hard work paid off, and the manager soon moved him to the kitchen, where he spent nine years learning the ropes of the restaurant industry and recipes.
In 2005, he decided he wanted to be 'a boss' and opened San Lucas Pizzeria.
He and his wife make most everything in-house and offer lots of Mexican street food favorites, like tacos, burritos and tortas, along with nearly 20 varieties of pizza.
From a teenager coming to this country knowing virtually no English, Valentin is now the proud owner of a pizza shop that The New York Times calls one of the top 22 in the nation.
"I feel like a superstar now," Valentin says.