Rinse the tomatoes and cut off a lid. Hollow out the inside of the tomatoes. Dab tomatoes dry inside with kitchen paper and season with pepper.
Peel and crumble the goat cheese. Chop the walnuts and roast them briefly in a small pan. Clean, rinse and finely chop the spring onions. Coarsely chop cranberries. Mix the prepared ingredients with cranberries, thyme and olive oil and fill into the tomatoes.
Put the lid on.
Wrap each tomato in an appropriately sized piece of aluminium foil. Grill on the hot charcoal grill for about 5 minutes.