Someday, when each of us is forced by redevelopment-agency storm troopers to eat supper in atmospheric Coldplay-soaked downtown fusion restaurants at 1 a.m., we may grow a little nostalgic for the days when late-night dining downtown meant the Pantry or nothing, when the party after a show at Al’s Bar or the Smell inevitably migrated to Suehiro, the TV Café or Canter’s. But at the moment, it is still almost novel to stumble through a maze of massive construction sites into a place like E3rd Steakhouse, which looks exactly like what Midwestern teenagers must imagine Los Angeles restaurants look like before they migrate to one of the local art schools, and whose great specialty is a few grams of grilled albacore held captive inside the core of a sliced and reassembled avocado. An Alba-Cado! Just imagine! E3rd, which looks as if it were assembled by Michael Mann’s art director, is nominally a steak house, a designy, halogen-intensive joint from the guys who run the loungy Korean-cum-Japanese Zip Fusion Sushi restaurants, but their signature beef and pork cuts are marinated to a candylike density, the mashed potatoes are enriched with spicy kimchi, and the jalapeño peppers come stuffed with tuna and glopped with sticky eel sauce — it’s a modern izakaya with training wheels, a user-friendly cocktail lounge with sleek cross-cultural eats. 734 E. Third St., downtown, (213) 680-3005.