Peel the seeds and cut them into strips, if the tomatoes are large then chop them too. Chop the garlic into 4 pieces.
The tongue needs to be cleaned and rinsed well. Make deep cuts in the tongue, fill the cuts with chopped vegetables. Top the tongue with salt and pepper to taste and oil, put a sprig of thyme. Wrap the tongue in foil and cook at 180 degrees for 1.5 hours.
Unfold the foil, remove the thyme and put the tongue back into the oven for 15 minutes. Before serving, cut the tongue into pieces.