Finely chop the vegetables and mash the garlic by removing the peel.
In a pan, brown the garlic and thyme in the oil, meanwhile cut the tempeh into regular and not too small cubes and, when the oil is very fragrant, add the chopped mixed vegetables and sauté well.
Also add the tempeh and, taking care not to break it, let it brown and flavour thoroughly until the cubes are golden brown on all sides.
Add the tomato sauce, cover and cook 1 hour on low heat.
Season with salt and pepper. The sauce can be kept in a special airtight jar for several days and used for many preparations.