Cut off top 1/4 of onion and reserve. Cut stem off bottom to keep from tipping. Scoop out centers of 6 onions leaving 2-3 outer rings about 1 inch deep at center. Chop onion centers, tops, 7th onion and reserve.
Preheat oven to 350
Place the 6 shells in lightly oiled baking dish and bake 10 minutes. Remove from oven and hold at room temp.
Sauté in 1/4 cup Grapeseed oil the meat. onions, celery, bell pepper, sage and oregano at med-high heat 8-10 minutes.
With no heat add 1 cup vermouth and stir in panko. Add more panko as needed to thicken stuffing.
Fill onion shells with stuffing.
Bring beef broth to boil then pour into baking dish about 1/2 inch deep. Add 1/4 cup vermouth to baking dish.
Bake onions for 15 minutes, then baste, cover and bake 15 minutes longer.
Transfer onions to individual plates. Boil remaining juice reducing by 1/2 and drizzle onto onions.