One of the city’s hottest new restaurants has neither Michelin stars nor menus, but it’s already fully booked until Christmas — when the eatery’s owner and chef, Jonah Reider, will close up for his semester break from college.

“I didn’t expect it to be so popular,” says Reider, 21, a Columbia University senior who opened a New American restaurant called Pith in his dorm room two weeks ago.

Four nights a week, he serves four diners a five- to eight-course dinner prepared in the common kitchen in his suite at Hogan Hall. Reservations, which he takes via Yelp, are open to both students and “randos” ­— of which he’s had a few. The dining room is the communal space he shares with three roommates, and the decor is classic dorm-minimalism — unframed art, old pizza boxes and halogen lamps.

“My roommates are chill with it,” says Reider, who studies economics.

On a recent night, dinner begins with artisanal cheeses, house-pickled red kale stalks and olives.

“These Zabar’s olives are so fire — that means they’re awesome,” says the young chef who’s loved to cook since growing up in Newton, Mass.

After the olives there are seared lamb chops with smoked paprika, barley with figs, and snow peas with pancetta and maitake mushrooms.

One of Reider’s roommates, architecture major Jordan Walters, 21, is a dinner guest.

“It’s definitely a lot of fun,” says Walters. “But it can be a strain since we have to study. I guess now with his fame, we’ll have to have a discussion.”

But while Reider is gaining fame, he’s not making a fortune. He charges just $10 to $20, and he says he doesn’t turn a profit. The university hasn’t interfered with his culinary extracurriculars. (Columbia didn’t respond to a request for comment.)

“How is it different from going to a party [where you] pay $3 for beer?” asks Reider.

The low cost doesn’t mean the menu is boring. Reider looks to restaurants like Per Se and Eleven Madison Park for inspiration, though he doesn’t follow recipes and he’s never eaten at either place — “too expensive,” he says.

At the end of the meal, Walters is complimentary but critical.

“New York City is known for having some of the best restaurants in the world,” he says. “If I compared his cooking to that, maybe he could dial in the spices more.”