Mix 1/3 cup brown sugar with water and lemon juice together in an ungreased baking dish until sugar is dissolved. Arrange pear halves, core side down, in the dish, and baste with the sauce. Cover with aluminum foil.
Bake pears in the preheated oven for 20 - 25 minutes, or until fork-tender but not mushy.
Meanwhile, mix nuts together with the remaining 2 tablespoons brown sugar, 1 1/2 tablespoons brandy, and the yogurt; set aside. In a separate bowl, whip cream until stiff peaks form. Sprinkle in white sugar and remaining 2 teaspoons of brandy, or liqueur of choice, and gently whip a few strokes more.
To serve, place one pear half in the center of each serving plate and fill core cavity with nut stuffing. Top with whipped cream. Serve warm.