1. For this recipe, I used a mason jar (mine was 24oz, any canning jar of approximately this size will work). It will help to get a crispy skin (the duck fat will drip down onto the vegetables, and the vegetables will get an amazing flavor). If you don't have a jar, you can still make this recipe, just place your whole duck (breast side up) on the vegetables.
2. Add beer to your jar (no beer? replace with cold water, we need to have some liquid in that jar, for it not to break).

3. Rinse the entire duck, inside and out. Trim the excess fat and skin around the neck and duck cavity opening. Rub the inside with salt and garlic powder.
4. Pat the skin dry with paper towels. With a sharp knife, make a few cuts on the breast. Cut through the skin and fat, but don't cut the meat. Then prick the skin all over with a sharp fork.

5. Place duck on the jar, you may need to slightly force your whole bird on the jar. Place the jar with the duck in a large baking dish / large roasting pan.
6. Rub garlic powder, paprika and salt into the skin of the duck. Add some precut vegetables of your choice (I use potatoes, carrots, onions and celery) to the bottom of the pan, lightly sprinkle with salt and pepper.

7. Adjust your oven rack so that the duck fits in the oven (it shouldn't touch the oven). Preheat oven to 425F (220C).
8. Roast the duck for 15 minutes, then reduce oven temperature to 350F (180C) and bake for another 1 1/2 - 2 hours (cooking time may vary depending on your oven), until golden brown and juices run clear (mine took 1 hr 40 min). Use a meat thermometer to ensure the internal temperature reaches 165°F (74°C) for juicy meat and fully cooked result. 
9. Transfer duck to a cutting board or serving platter. For best results, let duck rest at room temperature for 10 minutes before carving. Enjoy!