Preheat the oven to 170° C (340° F) and heat a large heavy-based pan or Dutch oven on the hob medium to high heat, and then add 1 tablespoon of olive oil.
When the pan is hot enough, add the beef cheeks and brown them on both sides. Do it in 2 batches to avoid overcrowding the pan.
Remove the beef cheeks on a plate and then set them aside.
Lower the heat to medium-low, add the rest of the olive oil and sauté the onions and the celery for a few minutes.
Add the carrots to the pan and cook them for a few minutes.
Add the tomato paste, flour, garlic, thyme, and bay leaves, and then give them a good stir.
Stir in the red wine and deglaze the bottom of the pan.
Add the stock along with the beef cheeks, bring the pan to a boil, close the lid, and put it in a preheated oven.
Cook the beef cheeks for 3 hours, or until they are tender and fall apart easily when touched with a fork. Make sure you check the stew every 40 to 50 minutes to make sure there is enough liquid to cook the beef cheeks.
Remove the bay leaves, check the seasoning and add some salt if necessary before serving.