Place a large heavy-based frying pan or skillet over high heat. Once the pan is very hot, add a drizzle of extra virgin olive oil and sear the sliced beef in 2-3 batches. Spread each batch in a single layer and cook for about 30-60 seconds – you are looking for good colour on the outside, not fully cooked through. Remove each batch and set aside on a plate. Do not overcrowd the pan, as this will cause the beef to steam rather than sear.

Once all of the beef has been removed and set aside. Reduce the heat to medium-high. Add the thinly sliced brown onion, and both the sliced portobello mushrooms, and sliced button mushrooms, to the same pan. The pan may look dry at first – resist the urge to add more oil. As the mushrooms cook, they will begin to release their moisture. Cook, stirring occasionally, for 8-9 minutes until the onion is soft and the mushrooms are golden and any liquid has evaporated.

 Add a drizzle of olive oil, then add the garlic, 1 teaspoon fresh thyme leaves, and 1 teaspoon smoked paprika to the pan. Stir well and cook for 1-2 minutes until fragrant. Sprinkle over the 4 tablespoons plain (all-purpose) flour and stir to coat the vegetables. Cook for a further minute to cook out the raw flour.

Pour in the 500ml beef stock gradually, stirring continuously to prevent any lumps from forming. Bring to a gentle simmer, then add the 1 tablespoon Dijon mustard and 1 teaspoon Worcestershire sauce, then stir through the 125ml sour cream. Simmer for 4-5 minutes, stirring occasionally, until the sauce is thick and glossy. Taste and season with salt and pepper.

While the sauce is simmering, bring a large pot of well-salted water to the boil. Cook the 385g dried pappardelle (or your favourite short pasta – conchiglie, rigatoni, or calamarata) according to the packet instructions until al dente. Before draining, reserve about 125ml of the starchy pasta cooking water. Drain the pasta, then return it to the pot and toss immediately with the 30g salted butter and a splash of the reserved pasta water until well coated, smooth and glossy.

Just before serving, add the rested seared beef back into the sauce. Simmer over medium heat for 2 minutes, until the beef is just cooked through and tender – be careful not to overcook it at this stage. Remove the pan from the heat. Spoon the stroganoff over the buttered pasta, scatter generously with 1 large handful of fresh flat-leaf parsley, finely chopped, to serve, and serve immediately.

Notes

• Aim to have your pasta draining just as you add the beef back into the sauce – that way everything is hot and ready at the same moment. The beef only needs 2 minutes in the sauce at the end, so don’t rush the pasta.
• For the best texture, slice the beef as thinly as possible (about 3-4mm). Partially freezing the fillet for 20-30 minutes beforehand makes this much easier.

Finely chop half the mushrooms, slice the remaining half.

Heat the oil in a large frying pan over medium heat. Add the brown onion and cook for 3-4 minutes or until soft. Turn heat to high and add the beef mince and chopped mushrooms. Cook stirring and breaking up lumps for 5 minutes or until mince and mushrooms are cooked. Add the garlic and cook for 1 minute. Add the thyme leaves, taco spice mix and 1 cup (250ml) water. Bring to the boil. Reduce heat to low and simmer for 5 minutes or until mixture thickens.

Meanwhile, heat butter in a medium frying pan. Add the sliced mushrooms and cook for 3-4 minutes or until golden and cooked. Reserve.

Warm the tortillas in a frying pan or char-grill pan over medium heat for 1-2 minutes or until slightly charred. Alternatively, warm following packet instructions. Keep the tortillas warm wrapped in a clean tea towel.

Fill the warm tortillas with lettuce and cabbage, top with the mushroom beef mixture and garnish with sliced mushrooms. Sprinkle with coriander and serve with lime wedges, tomato salsa and sour cream.