Combining melt-in-the-mouth beef, savoury mushroom duxelles and crisp golden-brown pastry, this is a real show-stopper, ideal for a special event.
Begin with the mushroom duxelles. Put the mushrooms in a food processor and chop very finely, almost to a paste.
Melt 20g Pure Slightly Salted in a large frying pan over a medium heat. Add the shallots and garlic and a little salt and pepper and sauté for 3-4 minutes.
Add the finely chopped mushrooms and increase the heat a little. Cook, stirring often, for around 10 minutes or until all the liquid released by the mushrooms has evaporated and they are well coloured and reduced in volume.
Add the wine and cook for a minute or two more until the liquid evaporates. Taste and add more salt and pepper if needed. Set aside to cool completely.
To make the pastry, put the flour in a mixing bowl and stir in a good pinch of salt. Use a box grater to coarsely grate the cold Pure Slightly Salted into the flour.
Use a table knife to stir and cut the Pure into the flour to create a lumpy mix. Measure out 150ml very cold water and add it slowly to the mix, bringing it together with the knife into a shaggy dough.
Finish by kneading lightly with your hands. Shape the dough into a rough rectangle, wrap and chill for at least 30 minutes.
Now brown the beef. Unwrap it and pat away any moisture with kitchen paper. Put on a plate and season well all over, including the ends, rolling the meat in the seasoning.
Heat 10g Pure in a large frying pan over a high heat. Add the beef fillet to the pan and brown it well all over, turning so that all the sides and each end get plenty of colour. This will take about 10 minutes. Set the meat aside to cool completely.
Cut the chilled pastry into two pieces: one-third and two-thirds. Put a piece of parchment on a tray or board that will fit into your fridge, and place the smaller piece of pastry on it.
Roll out the pastry so it is about 2cm larger all round than the beef fillet. Put about one third of the cold mushroom duxelles on this pastry and shape it so that the beef fillet will sit neatly on it. Put the beef on top. Using a fork and your hands, carefully pat the remaining mushroom duxelles all over the top and sides of the beef (don’t worry about the ends).
Roll out the larger piece of pastry so that it will comfortably cover the beef. Brush a little oat milk on the pastry around the beef. Carefully lift the larger piece of pastry over the beef and pat it down all around the base. Trim off excess pastry around the base, leaving a roughly 2cm border.
Use a fork or knife to press this border all round to seal. If you like, use the pastry trimmings to make some decorative shapes, adhering them to the Wellington with oat milk. Refrigerate the Wellington for at least 30 minutes.
Preheat the oven to 220C/fan 200C/gas 7 and put in a baking tray to heat up.
Brush the Wellington with oat milk then use the paper to transfer it to the hot baking tray in the oven.
For medium-rare beef, bake until the meat in the middle registers 50C on a probe thermometer – start checking after 25-30 minutes, giving it a few more minutes each time if it’s not quite up to temperature. For medium meat, bake until it registers 55C.
When done to your liking, remove from the oven and leave to rest for 10 minutes before slicing with a sharp carving knife. This is delicious served with wilted spinach and some crushed waxy potatoes.