Pat the beef fillet completely dry and season generously with salt & black pepper. Heat olive oil in a hot pan until smoking. Sear the fillet on all sides for 2 minutes. Brush all over English mustard, then leave to cool completely on a wire rack. Wrap in cling film and place in the fridge.

Blend chestnut mushrooms in a food processor until fine. Melt butter in a pan over medium heat and add shallots, garlic cloves and cook minutes until soft. Add the mushrooms and fresh thyme leaves. Add brandy and cook until completely dry with no moisture left. Season well and cool completely.

Blend spinach, egg, flour, milk and seasoning until combined into a batter. Cook the pancake in a lightly oiled non-stick pan. It should be thin and flexible and fully cooked. Cool on a flat surface.

Lay a large sheet of cling film on your work surface. Lay out the Parma ham slices, slightly overlapping, into a rectangle. Spread the duxelle evenly over the Parma ham. Lay the spinach pancake on top. Place the cooled beef at the near edge. Using the cling film, roll tightly into a cylinder, twisting the ends to compress. Refrigerate for at least 30 minutes.

After 30 minutes, unwrap the beef roll and place on the pre-rolled puff pastry. Roll up tightly, sealing the edges with egg wash. Trim any excess pastry, crimp the ends firmly, and place seam-side down on a lined baking tray. You can add a lattice for visual aesthetics. Brush all over with egg wash. Preheat your oven to 220°C / 200°C fan.

Bake for 20–25 minutes until the pastry is deep golden. For medium-rare remove at 52–54°C internal temp. Rest uncovered for 10 minutes before slicing. Slice confidently in the centre and serve immediately.