Preheat the oven to 220°C.
Season oxtail pieces with salt and pepper and dust with flour.
Roast oxtail in a tin for 30 minutes, turning halfway through to brown.
Sauté onion, garlic, and thyme in melted butter for 4 minutes until soft.
Stir in the 50g of flour and tomato purée.
Gradually whisk in red wine and beef stock and bring to a boil.
Add roasted oxtail, cover, and simmer for 2 hours until very tender.
Drain the oxtail and reserve the liquid in a bowl.
Remove meat from bones, return to pan with reserved sauce, and reduce until coated.
Whisk vinegar, mustard, and oil into a seasoned dressing.
Toss pea shoots, salad leaves, peas, and broad beans with most of the dressing.
Serve warm oxtail around the salad and drizzle with the remaining dressing.