Preheat oven to 200C.

Remove stalks from mushrooms and remove any dirt with a damp cloth. Season both sides with salt and freshly ground pepper and rub in 2/3rds of the olive oil.

Heat a large pan over medium heat and melt ¾ of butter and the remaining oil. Place mushrooms gill side down on pan and sizzle for 1 minute then flip over and sizzle for 2 minutes. Transfer to oven for approximately 8 –15 minutes (depending on size of mushroom), then lift mushrooms onto kitchen paper to drain, turning over once.

In a separate pan melt the remaining butter in a pan, add the spinach then cook for 2-3 mins over medium-high heat until completely wilted. Season with salt, pepper and pinch of nutmeg, then tip the spinach into a large sieve to drain thoroughly. When cool, squeeze out excess liquid.

On a lightly floured surface, roll the pastry out to €1/ £1 coin thickness. Using a cutter or saucer and a larger-size plate, cut out 4 discs about 5cm wider than the mushrooms (for the bottoms) and 4 discs about 10cm wider (for the tops). Re-roll trimmings if you need to.

Place the four smaller discs on a baking tray and top each one with a mushroom followed by 1 heaped tbsp of wilted spinach (the spinach shouldn't spread wider than the mushroom).Top the spinach with 1 tbsp (40g) goats cheese and then 1 tbsp onion marmalade.

Lightly whisk the egg white with a fork then brush the border (base) of each disc with egg white. Gently stretch the larger disc over the mushroom, trying not to trap any air. Press the pastry together with your fingers, then form a good seal by holding a sharp knife horizontally against the cut edge and gently tapping the pastry all round.

Make a fluted edge by pressing index finger and thumb firmly down on top of the pastry, giving it a slight twist as you move around till all the edge is fluted. Score lightly with a knife to let out any air. Brush each wellington generously with the egg yolk. Bake in oven @ 200C for 25-35 mins until golden and crispy. Leave to cool for a few minutes before serving.