Prick the skin of the duck with a fork and brush it with a the olive oil. Season the duck with the fresh sage, 1 teaspoon of garlic powder, salt and pepper. Place the duck on a lined baking sheet and let the duck come up to room temperature.
Heat the vegetable oil in a skillet over medium-high heat. Add the carrots, onions, and celery and cook until soft, about 5 minutes. Set them aside to cool.
Mix the milk and eggs in a large bowl with the nutmeg and add half of the bread pieces. Let this sit for 30 minutes to fully let the bread soak up the custard mixture.
Heat an oven to 350 degrees. Coat the remaining bread with melted butter and place in the oven for about 8 minutes or until the bread has toasted lightly.
Coat the Bundt pan with 2 tablespoons of softened butter, even if it is a non-stick pan.
Add the toasted bread, sautéed onion, carrots, celery, parsley, salt and pepper, and thoroughly fold everything together. Poor into the Bundt pan.
Put the bread dumpling mixture into an oven heated to 325 degrees and cook for 90 minutes. When done, remove and set aside.
Heat the oven to 375 degrees and then add the duck and let roast for about 30 minutes or until the internal temperature reaches 160 degrees, turning the duck every 10 minutes so that it cooks evenly and the skin gets crispy. When done, let the duck rest for about 10 minutes.
In a small sauce pan, melt the remaining 2 tablespoons of butter and stir in the flour to make a roux. Stirring constantly, slowly whisk in the duck and chicken stock. Add the remaining teaspoon of garlic, dried sage, salt and pepper. Simmer until the gravy has thickened.
Cut the duck and serve with gravy and slices of bread dumplings.