Preheat oven to 350 degrees F. Line twenty-four 2 1/2-inch muffin cups with paper bake cups. In a small bowl combine 2/3 cup of the sugar, the pecans, and 1 tsp. of the cinnamon; set aside. In a very large bowl stir together flour, baking soda, salt, and the remaining 1 tsp. cinnamon. Make a well in center of flour mixture; set aside.
In a large bowl whisk together the remaining 2 2/3 cups sugar, the pumpkin, oil, eggs, and bourbon. Add egg mixture all at once to flour mixture. Stir just until moistened. Spoon batter into prepared muffin cups, filling each about 3/4 full. Sprinkle with nut mixture.
Bake 25 to 28 minutes or until a toothpick comes out clean. Cool in muffin cups 10 minutes. Remove; cool on wire racks. If desired, drizzle with Bourbon Icing before serving
In a small bowl stir together powdered sugar, bourbon, and enough milk to drizzling consistency.