Peel, quarter, and blanch the Brussels sprouts in boiling salted water. Plunge into an ice water bath to stop cooking. Drain and set aside.

In a medium frying pan over moderate heat, saute onions in the vegetable oil until they caramelize nicely, about 8 to 10 minutes. Add shallots, ginger, and thyme. Season with salt and pepper and saute 3 to 4 minutes longer.

Add the brandy (or equivalent) to the pan, let warm briefly, then remove pan from the burner. Working very carefully, light the liquor with a long match and allow the liquid to reduce. As a safety measure, keep a lid nearby to douse the flames if needed; the liquor will flame about 15 to 30 seconds before going out on its own. Add cream, honey, and vinegar, then simmer until the sauce thickens about 4 minutes. Add the brussels sprouts and stir. Season with salt and pepper to taste. Garnish with fresh herbs, if desired.