Bake yams at 350 degrees until tender. Cut oranges in half. Scoop out pulp and chop up half of it. Peel yams; put into mixing bowl with chopped orange pulp, melted butter, sugar, nutmeg, cinnamon, half of pecans and Grand Marnier or Triple Sec. Mix well and stuff oranges. Sprinkle rest of pecans on top. Bake at 180ºC or 20 minutes.