Wash tomatoes and slice off the top. Scoop out the pulp. Pat the insides of the tomatoes dry with a paper towel and sprinkle them with pepper.
Peel and crumble the goat cheese. Chop walnuts and roast in a small pan. Wash green onions and slice them finely. Chop cranberries. Mix the prepared ingredients with thyme and olive oil, and fill in into the tomatoes. Replace the tops.
Wrap each tomato in a piece of aluminium foil and grill them on a hot charcoal grill for 5 minutes.