For the Wellington

1. With a light dusting of flour, roll out puff pastry to a 40cm x 30cm rectangle, and rest in the fridge.
2. On a clean, flat work surface, put down a large rectangle of cling film (60cm x 50cm) with a few layers and push out any air bubbles with a cloth. Lay out the bresaola into a rectangle shape, trim edges to achieve 35cm x 25cm.
3. In a large frying pan, heat 20ml veg oil, add chopped mushrooms and season with salt and pepper. Cook on a high heat until there is no moisture left at all in the mushrooms, add the Madeira, and reduce to a gentle simmer.
4. In a small pot, sweat down the shallots, garlic and thyme with 1 tbsp vegetable oil till soft, then add to mushroom mix. When Madeira has completely reduced and mixture is almost dry again, remove pan from heat and set aside mushrooms to cool. 
5. Put a blue jay cloth onto a plate and build a 20cm x 15cm rectangle of raw spinach on top, layering till you have used ¼ of the spinach. Lay another lightly dampened jay cloth on top and microwave for 1 minute on full power. 
6. Remove from microwave and roll out any excess moisture with a rolling pin, and lay the spinach across ¼ of the bresaola, leaving a 3cm border before the edge. Repeat process with spinach until the bresaola is covered. Now spread cooled duxelle mushroom across surface of spinach and carefully pat down.
7. Put a frying pan on a high heat, season beef fillet well, then rub all over with vegetable oil. When pan is smoking hot, carefully put beef fillet inside, sear for about 20-30 seconds, just to get a little colour all over.
8. Remove the beef fillet and lay horizontally across your mushroom mix. When cooled, rub beef all over with English mustard.
9. Lifting the cling film carefully along the front edge, roll the whole mix into a cigar shape till the bresaola is wrapped all around, and bring the cling film to join. Reach into each end, gently tuck down any excess bresaola and fold over cling film to seal in whole Wellington. Once the package is secure, wrap tighter using the cling film roll, going around it a few times, then pop into freezer for 10 minutes.
10. Remove pastry from fridge, cut off a 14cm wide rectangle off the top longer edge, and retain in the fridge for your decoration. Place remaining pastry onto baking tray lined with parchment paper, gently dust off any excess flour, and brush liberally with egg yolk. 
11. Remove Wellington from freezer and carefully cut off cling film, and transfer to line horizontally across bottom of pastry. Roll the pastry upwards, keeping it tight to the cigar until seam is across the bottom with about 3cm of overlapped pastry, and trim off any excess. Carefully crimp down each end of the Wellington and trim so there is just enough to tuck back under itself, and brush all over with egg yolk.
12. Either cut a trellis using a lattice roller cutter with retained pastry, or whatever design you like, and attach to outside of pastry. Brush this all with egg yolk and sprinkle a little sea salt over pastry. Set in fridge for at least 30 minutes before cooking.
13. Preheat fan oven to 190ºc and bake Wellington for 40 minutes, or until centre reads 35ºc with a temperature probe. Slide Wellington onto a cooling rack off of its parchment paper and rest for at least 25 minutes. Then cut with a sharp serrated knife and serve with gravy and roast potatoes

For the Roast Potatoes

1. Heat oven to 200 degrees/180 fan oven.
2. Put the roasting tin in the oven.
3. Peel the potatoes and cut each into 4 even size
4. And rinse them.
5. In a large pot add potatoes and water just to cover.Parboil for 6-8 min
6. Drain potato in a colander.Shake back and forth to fluff the outside.
7. Add duck fat into hot roasting pan and heat for 2 min until hot.Add the potatoes, shake them until
8. all coated in fat and add rosemary.
9. Roast for 20min and give it a shake and roast for another 20-25 min until they are golden and crispy.
10. Drain off excess fat and scatter with Maldon salt

For the Red Wine Jus

1. In a medium saucepan over high heat add oil, shallot and sauté.
2. Add garlic and sprig rosemary.Keep stirring so that it’s does not burn.
3. Add red wine and reduce to two thirds
4. Add veal stock and bring to boil.
5. Turn heat low and simmer until reduced to two third.Strain the sauce 
6. Whisk in butter and season to taste