2) Heat a large oven-safe skillet over a high heat, and add the oil. With paper towels remove all excess moisture from the outside of the beef, and season the beef liberally with salt and pepper on all sides.
3) When the oil begins to smoke, lay the beef fillets gently in the pan, making sure they are not touching. Cook for 1 1/2 minutes on each side, then put the pan in the oven and cook for an additional 10 minutes for medium rare.
4) Cut the puff pastry cup in half and place the bottom half in the centre of the serving plate. Lay a spoonful of spinach in the middle, top the spinach and with one of the fillets. Lay a spoonful of duxelles on top of the fillet and cap with the top of the puff pastry. Drizzle the plate with a tbsp of wine sauce.
For the spinach:
1) In a large pan heat the butter over medium heat. Once the butter has melted add the spinach and a pinch of salt and cook until the leaves have wilted.
For the duxelles:
1) Add the mushrooms to a food processor and pulse until they are extra-finely chopped. Meanwhile, heat the butter over medium heat in a large skillet.
2) Once the butter has melted add the mushrooms and large pinch of salt. Continue to cook the mixture, stirring often until the most of the mushroom moisture has evaporated. Add the thyme and melt in the liver pate. Check for seasoning.
For the wine sauce:
1) In a medium sauce pot over a high heat, add all the sauce ingredients. Cook until the liquid is reduced to 180ml.