Preheat the oven to 120°C/gas mark 1/2
To begin, braise the oxtail – this must be done a day in advance so the filling has time to set. Place a large, heavy-bottomed ovenproof pan (large enough to comfortably fit the pieces of oxtail) over a medium-high heat. Add the carrot, onion, garlic and thyme with a splash of oil and slowly caramelise the vegetables until golden brown and tender
Season the oxtail and colour in a separate sauté pan until golden brown. Place the oxtail pieces in the pan of caramelised vegetables and add the tomato purée and red wine. Stir, add the chicken stock and bring to the boil
Place a circle of baking parchment over top then cover the pan with a tight-fitting lid. Place in a preheated oven for 4–5 hours until the oxtail is tender and falling off the bone
Remove the oxtail from the liquid and set aside in a bowl. Strain the liquid into a bowl and skim off the excess fat. Transfer to a clean pan over a medium-high heat and reduce to a sauce consistency. Remember to constantly skim off any fat and impurities that rise to the surface
Pick through the oxtail meat, removing all of the bone and cartilage. Once the oxtail is picked and bone-free, set aside
Add the diced celeriac to a pan with enough oxtail sauce to cover and gently cook until the celeriac is soft
Remove from the heat, add the oxtail meat and season. Mix to combine, then form the mixture into 6 equal-sized balls (they should be the size of golf balls, about 4cm in diameter) – it is important to get the balls as smooth and round as possible. You may find it easier to wrap each ball tightly in cling film to achieve a smooth, round finish.
Chill the balls in the fridge overnight and set aside the remaining sauce for finishing the dish later
To make the pasta, mix all of the ingredients together to form a smooth dough. Wrap tightly in cling film and leave overnight in the fridge
On the day of serving, make the ravioli. Pass the pasta dough through a pasta machine until you reach the thinnest setting. Lay the pasta sheets on a lightly floured work surface then cut into twelve 8cm discs
Place six of the discs on a lightly floured board and then place an oxtail ball on top of each. Lightly brush the edges of the pasta with water and place the other disc on top. Crimp the edges together, being very careful to remove all the air bubbles, and ensuring there are no holes or gaps in the pasta. Once each raviolo is complete, place in the fridge
To cook the ravioli, bring a large pan of water to the boil and add a pinch of salt and a dash of olive oil. Once boiling, place all six ravioli in the water and cook for 6 minutes
While these are cooking, heat the oxtail sauce in a pan and sauté the spinach in a little butter. Season the spinach with salt and pepper and drain well
Divide the spinach between serving bowls. Remove the ravioli from the water, season with a little salt and place a ravioli on each mound of spinach. Spoon a generous helping of oxtail sauce over the top and serve immediately.
In partnership with Great British Chefs.