Melt butter and place on bottom of baking dish. Cut up cinnamon buns and place in baker. Whisk eggs, cream, cinnamon and vanilla and pour over cinnamon pieces. Sprinkle with chopped pecans and pour syrup over the top. Bake at 375 for 24 minutes. Remove and let sit for 15 minutes. Warm icing that came with cinnamon rolls in the microwave for 10-15 seconds on medium or 50% power. Drizzle over the top. Shake powdered sugar over the top and serve.