By Tom Sietsema Washington Post Staff Writer Sunday, Oct. 2, 2005 It's hard to resist the charms of Luigi Diotaiuti, the gregarious owner of Al Tiramisu in Dupont Circle. The last time I dropped by his Italian shoebox, I watched first as he seated a couple at a tiny table next to a painting of Neapolitan seascape ("Ah, you have a view!") and then roamed around the room, gleefully waving a bowl of fresh truffles under the noses of appreciative patrons. While the space is cramped and noisy, sparkling seafood and delectable pastas make up for those distractions. So when I heard Diotaiuti was taking over the quarters of the short-lived Opera on U Street NW, I was thrilled. The neighborhood deserves a good Italian kitchen, and the restaurateur's idea of small plates of Italian food and quality wines by the glass is precisely how many of us prefer to eat these days. Like its sibling, Al Crostino is welcoming. In its opening weeks, Diotaiuti presided over the dining room, an engaging master of ceremonies in white chef's jacket. As at Al Tiramisu, the two-level, lime green-and-lemon yellow space is pint-sized. "I wonder if they have tables in the bathroom," a friend joked after she and I were seated in a narrow corridor behind the central dining area. As a diner might expect, there are crostini on the menu. The selections are subject to change but have included toasted rounds of bread slathered with a mild chicken liver pate and anchovy-laced mozzarella --- my favorites --- as well as more routine minced roasted vegetables and porcini mushrooms. Beyond those nibbles, the menu reads much like that of Al Tiramisu, offering skewered seafood, lamb chops with a glaze of honey and balsamic vinegar, and, irritatingly, specials whose prices don't get recited by the server but are outside the average price of what's listed. There have been some perfectly pleasant moments during my visits. The kitchen proves that scallops and lima beans are suited for one another when the seafood is sweet and fresh and the vegetable is whipped into a silken, pale green puree for the scallop to sit on. Escolar is tiled in slices of zucchini so thin you can read through them and is lapped with a creamy and delicate sauce of mascarpone and prosecco. Lovely. Pastas include pillowy hats stuffed with minced mushrooms and ricotta cheese gilded with a buttery, sage-scented moistener. And the aforementioned trio of tiny lamb chops gets a nice boost from its tart-sweet sauce --- but not from the dull clump of chard that serves as an escort, along with slices of ordinary roast potato. Other dishes taste as if they hail from a different kitchen. The squid and shrimp skewer I gravitate to at Al Tiramisu is offered here as just some ordinary seafood in a tasteless crumb coating. I ordered the sliced steak after a server praised it as "off the hook!"; what I got was juicy but surprisingly tame, despite a scattering of shredded arugula and rosemary needles on the beef. Creme caramel makes me yawn, too, and "crunchy Italian cookies" turn out to be ordinary bite-size biscotti. Cheese --- and another glass of vino --- make for a stronger ending at what can only be summed up as Tiramisu Lite.