Marcella’s Mia Sorella, in a new shopping plaza along Clayton Road in Ballwin, is a sibling to brothers Steve and Jamie Komorek’s upscale south-city restaurant, Trattoria Marcella. It is not, however, an identical twin. This is a more casual affair, big as a barn and about as noisy, with a vibe more conducive to large gatherings of family and friends than to candlelit canoodling. The menu features thin-crust pizzas and, lovers of St. Louis-Italian cuisine will be happy to learn, über-generous portions of pasta. For the non-T-rav-and-red-sauce crowd, pizzas are a better bet, either a build-your-own option or one of the specialty pies, such as the one with a roasted-garlic crema, prosciutto cotto, spinach and Gruyere. More reminiscent of Trattoria Marcella, a few traditional entrees — chicken Milanese, shrimp scampi, beef braised in Barolo — are also available.