Preheat oven to 350°F. Sauté onions in olive oil. When the onions are getting limp, add the mushrooms. Stir in vermouth and soy sauce and remove from heat. Slice the top off the brie, but leave the sides and bottom intact and place in an oven-proof serving dish (preferably round). Pour mushroom mixture over the brie and bake for 20 minutes until the brie has melted. Garnish with parsley or kale and serve on sliced French bread or crackers.