Holidays with Luann de Lesseps are not the lavish affairs filled with goblets of champagne and heaping bowls of caviar that one might imagine. After all, the Real Housewives of New York star is a former countess who literally wrote a book on upscale entertaining. But when the Connecticut native gathers with her six brothers and sisters for Thanksgiving in her hometown, the lunchtime meal is a decidedly down-to-earth feast. Think fried turkey over filet mignon. “It’s one of my...