Soak the wheat for 12 hours in plenty of water. Rinse in a sieve, drain then place in a saucepan with about twice the amount of water.
Bring to the boil, reduce the heat and simmer, covered, for 1 hour until the wheat grains start to pop up.
Peel and dice the onions.
Melt the butter in a pan and fry the onion until softened. Add the thyme.
Add the drained wheat grains. Wash the tomatoes, halve, deseed and dice. Place the tomato cubes and 2 tbsp crème fraîche into the pan.
Allow to simmer, stirring occasionally, until the liquid has almost completely evaporated. Season and leave to cool.
Mix in the oats, breadcrumbs and flour. Stand for 10 minutes.
Using damp hands, shape the mixture into patties.
Heat the rapeseed oil in a pan and fry the patties until golden brown on both sides.