Recipe of the week: Quality Chop House's roast cod, trotter tortellini, baked onion

Serves 2

Trotter tortellini

• 2 pig's trotters
• Salt
• 200ml chicken stock/water
• Sprig of thyme
• 2 bay leaves
• 2 garlic cloves
• 100g Lyonnaise onions (see below)

Burnt onion stock

• 2 white onions
• 300g reserved trotter stock
• Sprig of thyme

Pasta dough

• 500g ‘00' flour
• Pinch of salt
• 240g free-range organic egg yolks, plus extra yolk for sealing
• Dash of extra virgin olive oil
• Dash of water

Baked onion

• 1 small white onion
• Olive oil, for rubbing
• Salt, to taste

Roast cod

• 2 x 150g cod fillets
• Olive oil, for frying
• 40g butter
• 1 lemon wedge
• Salt, to taste

Lyonnaise onions

• 6 small white onions, thinly sliced
• 150g sliced beef fat
• 2 tsp salt
• ½tsp picked thyme leaves

First make the Lyonnaise onions. Combine the onions with the beef fat and salt in a heavy-based saucepan and place over a low heat. Add the thyme and gently stew until the onions begin to caramelise, stirring occasionally. This takes a couple of hours to do properly. When the onions are a rich golden brown colour, remove from the heat and strain off any excess fat. If you want to store them for a few weeks, don't discard the fat but leave it covering the onions to preserve them.

Then, make the tortellini filling. Put the trotters, stock, salt, herbs and garlic in a large saucepan and bring to a simmer. Gently cook for four to five hours until the trotters are very tender with the meat starting to fall off the bone. Remove the pan from the heat and leave everything to rest for one hour in the stock. Carefully remove the trotter and pass the rest of the stock through a fine sieve. Leave the strained liquid to one side – you'll need it later.

Pick the meat away from the skin and bone of the trotter – this will take patience but bear with it! Combine the picked meat with the Lyonnaise onions and a pinch of salt. Have a taste and, when you're happy with the seasoning, transfer to a piping bag.

Now make your burnt onion stock. Cut the onions in half, leaving the skin on. Heat a heavy-based saucepan and lay the onions in, cut side down to blacken – this will take about 10 minutes on a medium heat. Transfer the onions to a clean saucepan and cover with the reserved trotter stock, thyme and a pinch of salt. Heat the stock to 80°C and cook for three hours, making sure it doesn't boil. The resultant stock should have a beautiful roasted onion flavour with a lush pork depth. Pass this through a fine sieve.

Whilst your stock is on the go, make your pasta dough. Place the flour and salt in a food processor. Begin blending. Slowly add the egg yolks and, every now and then, stop the machine and scrape down the dry patches on the sides of the bowl. Add the oil and the water. The dough should form nice fine breadcrumbs and then eventually come together.

Shape it by hand into two even portions and wrap in cling film. Chill for at least 30 minutes before rolling out. Roll out the dough using a pasta machine, until you get to the second to last thickness. Use a 6cm cutter to stamp out discs of dough. Cover these with a cloth as you go to prevent them drying out.

Pipe about one teaspoon of trotter mixture into the centre of each disc then lightly brush the egg yolk around the outer rim of the dough. Pick the disc up and gently pinch together the top and bottom to enclose the filling. Lightly press the sides together until the tortellini is sealed, then pinch the two corners together to form a curve. Rest on a tray until needed.

To make the baked onion, preheat the oven to 170°C. Coat the onion in a touch of olive oil and salt. Place in a roasting tray and bake for 14 minutes.

Meanwhile, season the cod and heat some olive oil in a frying pan over a medium heat. Add the cod to the pan and gently pan-fry skin-side down for 3-5 minutes. Add the butter to baste the fish and turn it over, cooking for another minute or two. Finish with a squeeze of lemon, then remove from the pan to rest. Check the temperature of the fish with a probe – it should be 42°C or just above.

While the fish rests, bring a large saucepan of salted water to the boil and cook your tortellini for 2½ minutes. Peel the baked onion, cut into quarters and separate into petals. Get your two bowls and place a cod fillet in the bottom of each one. Arrange the tortellini and onion petals around, then pour over the onion stock. Finish with a drizzle of olive oil.