Stella didn't invent the notion that a Neapolitan-style pizzeria could become the new neighborhood bistro. But in Philadelphia, at least, Stephen Starr's stylish take on the concept three years ago focused on serious wood-fired pies, fresh salads, and prices still within reach of local regulars, certainly landed ahead of the trend - and has remained influential.

We've already seen several worthy competitors follow, from Nomad (my fave so far) to Phoenixville's Vecchia Pizzeria (its menu limited, but the Regina pie is the best bufala mozz Margherita I've tasted around here yet). And with recent openings such as Bufad on Spring Garden (from the owners of Cafe Lift) and much-anticipated projects to come from Zavino (a branch planned for Drexel University) and Italian king Marc Vetri (near the Barnes Foundation), Philly's pizza party has only just begun.

A pair of other projects, however, which appear most distinctly inspired by Stella - District 611 and In Riva - show how tricky this seemingly simple concept is to perfect and expand upon.

District 611 is across the Delaware in Riverton, where three Starr alums (Brian Baglin, Catherine Piotrowski and chef David Perini, plus partner Jim Brandenburger) have brought a tiled wood-fired oven and an urban vibe to a South Jersey strip mall, from the tall-top community tables to the name itself (a dual nod to Philly's Broad Street and the Riverton address). The overly ambitious, catchall menu, though, is too unfocused, ranging from spicy lime chicken wings (chewy and burnt) to Asian-fried rock shrimp with pineapple (fruity and soggy), pasta in too-sweet tomato sauce, and dry roast chicken with yellow diner-thick gravy.

The pizza, though, was especially disappointing. Despite the Italian "00" flour and imported buffalo mozzarella, the so-called traditional "D.O.P." Margherita (made according to strict Italian guidelines) was a disaster. The crust was both misshapen and leaden, with so much chunky tomato juice flowing across its doughy face, it would have been better labeled soup.

As we got into the car, and a charming young Rivertonian mooned us at a nearby intersection on our way to the Tacony-Palmyra Bridge, I knew it was a sign.

District 611 needs more time.

Arthur Cavaliere's In Riva in East Falls is proof that a little time can be worthwhile, based on the improvements I've tasted in its first year. It sits beneath the Roosevelt Boulevard overpass at a Ridge Avenue address with a long history of failed and shuttered businesses (remember Verge?).

But developer Mark Sherman's riverside building has a scenic terrace overlooking Kelly Drive and tons of potential, like underserved East Falls itself. And if the issue is simply an elusive concept, Cavaliere, who worked six years for Starr (El Vez, Parc, Buddakan A.C.), made a smart call with his Stella-inspired pizzeria. Even if pizza isn't what he does best.

The look is casual and current, with industrial-chic walls of exposed cinder block, a high iron ceiling, and a community table made from an old barn door set beneath a plank chandelier illuminated by desk lamps. The bar is stocked with craft beers and Italian brews (try the Brutons) and a small but fairly priced list of Italian wines - even more affordable on half-price-bottle Wednesday nights.

And the beauty of those Neapolitan-style pies - their lighter, smaller rounds versus the heartier, crispy crusts of traditional East Coast styles - is the ability to offer a wide variety of updated flavors without breaking the appetite or the bank, with all selections under $20.

The challenge in making great Neapolitan pizza, though, is that getting just the right light touch on its basic elements - dough, sauce, toppings - is deceptively hard. And while Cavaliere's pies are considerably better than District 611's, I've not exactly been wowed, either.

His Neapolitan dough, by definition softer than more familiar American styles, is still too soft for my tastes, its crown too easily blistered without enough toothy pay-off on the bottom. The charring, though, has been more restrained of late.

And while I still don't love In Riva's most basic pie - the Margherita's raw tomato sauce is too sweet, the dry loaf-mozzarella not weepy-moist enough - I've come to enjoy his more elaborate efforts. The cooked red sauce for his meat-centric pies is more balanced, and perfectly tuned to the shaved rounds of soft meatballs dolloped with creamy ricotta beneath the roasted snap of mildly spiced shishito peppers. The "broccoli misti" with rabe, florets and smoked scamorza is for those who crave spicy, crunchy, bitter greens. The "Irlanda," topped with brussels sprouts, cooked Italian ham, and aged balsamic, as well as the unusual potato and gorgonzola pie, tweaked French with leeks and bacon, show seasonal appeal.

But the most compelling improvement at In Riva (which means "on the bank") has come with Cavaliere's willingness to flex his kitchen chops - also honed with Jose Garces (Amada) and an exec chef job at Central Michel Richard in Washington D.C. - to go beyond the pizzas with Italian small plates and surprising pastas.

His crispy artichokes with olives and lemony yogurt alone are worth the bike ride from Center City. But I'd plan a longer loop to stoke an appetite for many others - the crispy fingerlings dunked in a jar of warm truffled Fontina cream; or his braised pork ribs glazed with Italian agrodolce beneath shredded apples and pistachios; crispy (yet soft inside) rounds of octopus that recall his Amada days.

In warmer weather, I can imagine lolling post-ride on the terrace with an icy Frigo cocktail (Campari, Falanghina wine, and vivid orange soda), and a mason jar of refreshingly tangy pepperonata salad of roast peppers and lump crab to spread on grilled bread. Or cool and creamy burrata cheese with tart pickled tomatoes for a fun twist on old Caprese. Or Cavaliere's bitter green take on grilled Caesar, swapping escarole for the usual romaine.

The biggest surprise, though, has been the recent addition of inventive handmade pastas, which come in appetizer portions for $11 to $14, or a shareable trio for $33. The kale-greened gnocchi would have been ideal had the braised short ribs on top been more tender. But the gossamer-thin agnolotti wrapped around silky pea puree with truffled oyster mushroom sauce were delicate and stunning. But my new favorite, the dowel-wrapped garganelli pasta quills tossed with a spicy ragu of house-ground Italian fennel sausage, chopped rock shrimp, and basil, achieved the neatest "Riva" effect of all: evoking the banks of the Mediterranean, rather than the Schuylkill.

These virtues alone should be enough to win In Riva a loyal crowd as an East Falls anchor. I'm hoping that someday the already good pizzas rise to that level of greatness, too.


Next Sunday, Craig LaBan reviews the new Fond. Contact him at claban@phillynews.com.