Unless you live under a rock, you know that pretty much everyone in the city is obsessed with Che Fico, the Fillmore's new Italian restaurant from award-winning chefs Angela Pinkerton and David Nayfeld and ops man Matt Brewer. (Even celebs are obsessed—ahem, Gwyneth Paltrow).

Now, quick on Che Fico's heels and located just downstairs, the pair are upping the ante with the more casual sister restaurant Theorita, fashioned after a midcentury diner and serving up all those fried and sugary classics but with a decidedly San Franciscan twist.

Designer Jon de la Cruz (Che Fico, Leo's Oyster Bar) put a slick urban spin on 1950s diner style for the interior of Theorita.

But forget your notions of Che Fico's moody design and $40 pasta—Theorita is cheap-chic. Well, $15 for a burger isn't exactly cheap, but that will be your biggest splurge of the meal (unless, of course, you spring for an entire $34 pie). With the same team at the helm, you might get the sense that Theorita serves the kind of food the chefs want to eat off-duty: hearty, satisfying, no fuss (well, maybe a little), and no fancy wait time.

In fact, Theorita is prepared to be a grab-and-go affair—all orders are taken at the counter, where you'll be hard pressed not to order a half-a-dozen pastries to go. But if you are in the mood to linger beneath bright local art in a plaid-upholstered booth, you'll be rewarded with comfy, off-beat decor and modernized diner fare.

Now serving breakfast, lunch, and dinner, Theorita makes even a simple English muffin special, serving it with jam, yes, but also with rich, whipped foie gras butter. The very melty burger gets a boost from a double patty and a soft potato bun, and the fried chicken sandwich, with bird from Marin Sun Farms, gets a helping of housemade sriracha. Want fries with that? They'll be crispy, skinny, and topped with healthy pats of butter, because reasons.

Should you be in need of something lighter, there's a bomb vegetarian chili served with Southerner-approved maple cornbread and even a few salads with the power to lure us away from our weekly runs to Souvla down the street.

  

The housemade English muffins are like none you've ever had, teamed with whipped foie gras and Swanton Berry Farm's strawberry jam. In the morning, these muffins also make delightful breakfast sandwiches.

// Theorita, 834 Divisadero St. (Fillmore), theorita.com