Heat a little olive oil in a large skillet, add garlic, thyme, mushrooms, salt, cook over high heat until golden, 7-10 minutes. Chop them. To book.
Cook the bulgur according to the package directions. Then mix the bulgur and the mushrooms, add the liquid cream, salt and pepper.
Meanwhile, add a little oil to the skillet, add the celeriac strips and brown them in the skillet, about 5 minutes. They should be just tender. To book.
Preheat the oven to 180°C.
Take a charlotte mould, for example, oil it, and place the celeriac strips by overlapping them, go up on the sides, then add the bulgur/mushroom mixture, close with other celeriac strips.
Put in the oven for 20 minutes.