Oyster Bay is having a restaurant boom, between the Sicilian-inspired newcomer Autentico, the newly opened Spinnakers in what used to be Jack Halyards, and a second location for Nikkei of Peru in the works. Compared to Autentico, Osteria Leana is the more casual Italian spot, a 40-seat little hideaway with an entrance facing its South Street parking lot.

Chef-owner Peter Van Der Mije moved with his family to Long Island five years ago, having grown up in Florida and Colorado. He brought with him experience, working in Manhattan under celebrity chefs Jean-Georges Vongerichten at Nougatine, Marcus Samuelsson at Aquavit and Dan Kluger at The Core Club. Before that, he attended the Culinary Institute of America in Hyde Park as well as Cornell’s hotel school, where he earned an MBA.

This place has potential. With a brief menu that changes with what Van Der Mije finds at farmers markets, it’s a mix of straightforward and unusual preparations such as a creative take on a calamari starter and a simple-yet-impressive cacio e pepe pasta. All of the dishes are easy to mix and match, with portions neither oversized nor skimpy.

You can see Van Der Mije in the open kitchen just about every night. The small bar tucks into the back corner while a communal table stands at the center of a space that fills up on weekends and on rainy summer nights.

Service is on-point, from the socially graceful hostess to service director Juan Carlos Ortiz, who oversees the dining room with a hawk eye. You will never be neglected here, and if the restaurant isn’t full, you might see a server one time too many — better than the opposite scenario.

The most refreshing starter is the cucumber gazpacho delivered as a bowl alongside mascarpone toast with tomato jam, the bright green soup poured tableside. Tomato watermelon panzanella, listed under sides, is a runner-up, its produce dotted with garlicky croutons, drizzled with shallot dressing, served with a smattering of feta and ribbons of basil.

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Sicilian olives are indulgent, stuffed with sopressata and pork, fried with a bread crumb-cornmeal combo. The Montauk calamari is a welcome surprise with an unusual preparation: grilled over very high heat, seasoned with salsa verde, accented with red peppers and served on roasted Yukon Gold potato salad with olives.

Among pastas and main dishes, diners gravitate toward the chittara, an egg pasta that’s a bit like linguine with more texture, served here with a corn basil pesto, trumpet mushrooms and scallions, and the option to add lobster, which, of course, most people do. The components are pretty wonderful, but my first order was undersalted and fresh noodles stuck together stubbornly. A server saw it and whisked it away, returning minutes later with a refreshed plate. Cacio e pepe is a simple and near-perfect rendition of pasta with olive oil, butter, black pepper, and grated cheese, a relief, as so many restaurant versions are overwrought with extra ingredients or pasta served well past al dente.

Seared scallops in citrus clam broth is my favorite entree, layered with julienned vegetables. A classic done well, veal Milanese arrives with a side of haricot verts. Usually a breakfast dish, eggs in Purgatory is dressed up by a large duck egg served with tomato sauce on a slab of fried polenta, the whole thing spiked with sofrito and salsa verde. It’s surprisingly hearty.

Both times I visited the restaurant, it didn’t fill up until after 8 p.m., when a group celebrating a birthday arrived and commuters filed in on the late side. As the sun sets and the staff lights candles, you’ll find Osteria Leana most hospitable: a romantic hidden gem where the simple preparations done well display confidence and the skill of the chef.