Preheat the oven to 150°C, fan 140°C, gas 2. Heat half the olive oil in a medium non-stick saucepan. Dust the pork with the flour. Add half the pork to the pan and brown on all sides. Remove to a plate. Repeat with the rest of the pork and set aside.
Add the remaining olive oil to the pan, along with the onion, carrots and celery and cook, stirring occasionally, for about 10 minutes, until the onion has softened slightly. Return the meat to the pan with the garlic, tomatoes, bay leaf and thyme leaves. Make up 500ml stock using the stock cube and pour 300ml into the pan (save the rest for another recipe). Bring to the boil, then carefully pour the contents of the pan into an ovenproof casserole. Cover with a lid then transfer to the oven and cook for 2 hours.
Just before serving, remove the casserole from the oven, sprinkle with the grated parmesan and bake until the cheese has melted.