"Our menus change with the seasons. It is our mission to provide customers with the purest and finest local ingredients and to support farmers who take great pride and passion in their work." Yeah, yeah, right. Heard that one before — like every single time a restaurant opens these days. But the owners of Sustain, which began operating this past year alongside Mercadito and Sugarcane Raw Bar Grill on a suddenly hot stretch of midtown, are actually keeping their word. Most emblematic of Sustain's honest approach to American cooking is the signature "50 mile salad," composed of seasonal products such as Borek Farms beets roasted in a wood-burning oven, Teena's Pride heirloom tomatoes, pickled onions, spicy brassica greens from Paradise Farms, and fromage blanc from Hani's Farm ($9 small/$16 large). The named farms are in or near Homestead, and every ingredient in the medley is plucked from within a 50-mile range. The rest of the menu likewise pays homage to sustainable foods, which would amount to squat if the stuff didn't taste outrageously good. But here it does.