Preheat the oven to 350°F. Butter a large ramekin or small soufflé dish. Line the sides with doubled parchment paper to give the dish a 2- to 3-inch collar.
In a bowl, stir the ricotta, Parm, pistachios, egg, thyme, lemon zest, salt, pepper and a few grates of nutmeg. Scrape into the ramekin, set it on a baking sheet, and bake until just set, about 45 minutes. Let cool for 30 minutes or so.
Remove the parchment paper collar and turn out the baked ricotta onto a serving dish.
“Baked cheese is delicious all on its own, served with flatbreads, crackers or charred toast. Ripe, fresh fruits are also delicious with baked ricotta. At holidays, top this stunner of a snack with roasted grapes, roasted cherry tomatoes or roasted pitted cherries. I roast all three of these fruits as toppers with thinly sliced shallots and a fat drizzle of good-quality balsamic vinegar.”