What: Diage has dropped its everyman Western menu, and picked up a funky Spanish “tapas and rice” concept.

Look: Newly orange walls and old brick archways, and big windows that look out over their urban garden. Whimsical watercolors of pigs, fish, and leeks illustrate banners at the entryway, and the menu.

Food: As namesake chef, Willy, told us, “Tapas and rice, from modern to traditional.” Gazpacho in two textures; kingfish in vinegar, with garlic, parsley, and salmon eggs; cuttlefish in traditional fisherman’s broth with chocolate and olives; pigeon with grapes; and 11 paellas, from a runny house version with crab, artichoke, and marrow bone to a black truffle and pumpkin “creamy rice.” Lunch is more traditional.

People: Nearby office workers and Japanese lunchers have always loved this space. Dinner will be for nibblers.

Bill: Tapas ¥32 to ¥65; rices and paellas, ¥140-160 (for two). Set lunches, ¥48-¥98.

El Willy had us at the pan con tomate. Tomato with bread. It’s the complementary little starter as you’re looking over the menu, and it was done right: crusty, warm bread, tomatoes that, surprise, tasted like tomatoes, a bit of olive oil and garlic, and not much more. It’s the simplest thing on the whimsical, creative menu, and is followed by all kinds of more complicated dishes – a sharp gazpacho with a mild coconut sorbet and soft, briny pieces of sea urchin, a rectangle of par-cooked foie gras and crispy eel so fatty it’s served with a butter knife and more crusty bread, and rich braised beef cheeks on top of crispy parcels of fried banana. Somewhere in the middle fall classic, undeniable combinations with a modern twist here and there – a low-temperature poached egg over slices of fried potato as thin and crisp as potato chips, scattered with Iberian ham, both its yolk and white soft and runny from its scientifically informed cooking. Or mild, raw scallops sliced into pearlescent coins, draped over a creamy avocado puree, and sprinkled with crunchy fried shallots for a bit of texture.

There’s no doubt The Willy can cook, and cook well. We prefer his more adventurous tapas to his subdued menu of paellas and “juicy rices”, though the jet-black ocean of a squid ink paella studded with cuttlefish stands out. And it’s this menu – tapas both including and going far beyond the pan con tomate, and conservative but equally good rice dishes – coupled with lowball prices that allow adventurous grazing, that have turned Diage around. (Diage is the colonial villa, El Willy the restaurant; there is also a pricey, upstairs hair salon called Coloriste, and Ushigokoro, the “small, small museum,” on the ground floor.) Six months ago, it was a gorgeous, but empty house; save for lunchtime crowds from K.Wah and a Japanese contingent (who have also picked up on the major change and are at El Willy in even more substantial numbers). The staid menu of Caesar salads and average burgers left the owners with more rooms than they knew what to do with. Now, the slick black-leather lounge is crammed with people vying for a table; the downstairs wine cellar is filling up with rare, hand-carried Spanish wines; the al fresco terrace buzzes until late in the evening, every day but Sunday.

There’s no secret to the newfound blazing success of El Willy; it’s the food. More precisely, it’s the details in the food, the obvious care and focus that was as evident in that first slice of pan con tomate as in the last bite of apple consomme, charged with chunks of blue cheese hidden among the fruit. You can look closely, with the critical eye of the foodie, and you’ll see the quality ingredients, the precision, and unexpected complementary flavors. But it’s hardly necessary. His combinations are never difficult for the sake of it; in the end, the pan con tomate and the foie gras with eel have one major trait in common – they’re delicious.