TAMPAIn metro areas where restaurants densely stud every street, entrepreneurs have gotten tunnel vision: Serve a single food, do it right, carve a niche, plug it on social media, watch the lines grow. In New York alone, you'll find the Meatball Shop, S'Mac (mac and cheese mania), Potatopia (all spuds, all the time) and an all-rice-pudding spot called Rice to Riches.The Tampa Bay area, with limited pedestrian culture, has been a little slow to the trend. Often food trucks pave the way for these single-subject restaurants, foot traffic driven by come-hither Instagram shots of artisanal doughnuts or dumplings.All of that is changing. In the past few weeks, Tampa has launched three single-subject concepts, all interestingly linked by the presence of ooey, gooey cheese (saturated fat is back, yeah!). Dough, the next-door younger sibling to Datz, has been revamped to showcase a gorgeous short menu of grilled cheeses. Right near University of Tampa, Max & Chz has opened to capture the late-night, missing-home mac-and-cheese-munching crowd. And further south, Spartaco Giolito has debuted Mr. Lasagna on the strength of the stunning lasagnas at his flagship Osteria Natalina.For the restaurants, a narrower focus means smaller kitchens, less waste, even leaner staffing. But there are upsides for customers, too. As Suzanne Perry, co-owner of Dough and Datz, notes, "With grilled cheese, it's about speed. You can get in and out in minutes, which is critical in a lunch environment. Anything that keeps your labor low and (your) speed up."DoughPerry herself is enthusiastic about the proliferation of single-subject restaurants (her personal favorite is Peanut Butter & Co. in Greenwich Village), but she says it's not altogether new."If you think about it, that's what a pizza place is, or KFC. It's not a foreign concept."Her recent decision to retool Dough's culinary mission had lots to do with its positioning with Datz."We always knew that we wanted Dough to have its own identity, so we initially tried a more feminine fine-dining experience. Meanwhile at Datz we were getting repeated requests for grilled cheese. I'm a little slow to catch on."This new Dough is fronted by oversized pop art posters of giant grilled cheese sandwiches. Sheer truth in advertising: These babies are huge, buttery, gooey with cheese and served with punch pickles (dill pickles dyed in lurid-colored fruit punches). Dough makes all its own bread (as well as that for Datz and the new Roux), from a crunchy-sturdy ancient grain bread to sourdough, a twisted pretzel bread and a few others. Eight combos (all $7) are paired carefully with the most suitable bread (okay, there's one called the Gidget Goes Hawaiian that beds down on a glazed doughnut). You can go it Old School (two cheeses on Amish milk bread) or get crazy with something like You Can't Curry Love (roasted poblanos, pepper jack, curried brown butter). For me, the Odd Couple was moan-worthy, goopy Brie married with sharp cheddar and contrasted by soft roasted red peppers and baby spinach.Max & Chz "Who doesn't love macaroni and cheese?" was the question owners Theresa Quibell and Luanne Russo and general manager Greg Artale posed. Yes, there are some mac haters out there, but University of Tampa students don't seem to fall in that camp. In what was once a tiny hot dog spot, Max opened in August with a little ordering counter from which you can select from a dozen types of mac offered in 5- or 7-inch aluminum tins. The larger version amply feeds a few people, even of the got-the-munchies variety.This is serious comfort food, with straight-up classic mac swirled with a Velveeta sauce ($4.50, $5.50), a broccoli and cheddar version ($5.75, $6,75, although I'd like to see a good bit more broccoli in this one), an alfredo that gets an Italian accent with asiago and Parmesan and small flecks of bacon for textural interest. Max & Chz has no liquor license, but here's what you do: Put your order in, grab a table next door at the Retreat (hey, happy hour wines are $2.50) and Artale will deliver your mac. The most interesting was the Southwestern version ($5.75, $6.75), a kind of tacos-meet-mac with seasoned beef, Jack and cheddar, jalapenos and tortilla crumbles on top. (And get this: There's a grilled cheese with mac and cheese in the middle. Whoaa.)Mr. Lasagna Spartaco Giolito has been a South Tampa fixture forever, years ago as a familiar smiling face at Donatello, then at his own eponymous restaurant, Spartaco, and then at his second restaurant, Osteria Natalina, named for his mom (who herself was a familiar presence in his kitchens). At Osteria, the menu is short but Giolito will stop by the table and say things like, "What do you want? You like-a marsala? I can make-a marsala, whatever you want."What sensible people have wanted are his delicious housemade strozzapreti (that means "priest choker," but it's not a particularly violent dish) studded with seafood, and his lasagnas, which change every few days to suit his whim. It could be a decadent mixed seafood lasagna lush with ricotta and nubs of shrimp and scallop, or a sturdy beef oozing velvety bechamel with just a whisper of bright tomato sauce.Mr. Lasagna, Giolito's grab-and-go idea, was a long time in the making, with build-out and permitting issues delaying the opening until the beginning of October. Although there are a few small tables, it reads like a takeout place, the Styrofoam clamshells carefully wrapped in plastic to ward off mishaps. Portions ($12-$13.50) are large for one person but a little scant for two — it might be nice, especially once evening hours are added, to offer a single-serving size as well as a family-serving size. From the veggie version packed with still-toothsome rounds of yellow squash and such, to the traditional beef entry, this is good lasagna using fresh pasta sheets, a textbook white sauce and a tomato sauce pinked delicately with cream.Although lasagna is the anchor, a trio of salads ($6.95) and things like eggplant rollatini ($7.50) can add up to an emergency take-home dinner in a jiffy.Contact Laura Reiley at [email protected] or (727) 892-2293. Follow @lreiley. She dines anonymously and unannounced; the Times pays all expenses.