Wash the pork ribs and pat them dry. Coat the oven pan with oil. Place the ribs on top. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for approx. 45 minutes.
Clean, peel, wash and cut the celery into 1-2 cm cubes. Clean, wash and cut leek diagonally into thick slices. Peel and finely dice onion. Heat the fat in a pan and fry the onion cubes in it until transparent.
Deglaze with vegetable stock. Let it simmer a little bit. Add the celery and leek, season with salt and pepper and add everything to the spare ribs on the fat pan about 20 minutes before the end of the frying time and braise.
Arrange the vegetables and spare ribs on a plate and serve garnished as desired with parsley and thyme.