Ten minutes later I was in my kitchen, tearing away the packaging and trying to figure out how I would cook them. I'd kill for a cryovac machine. They eventually went into the oven at 55ºC for 1.5 hours, looking very strange indeed with their layers upon layers of plastic wrap.
I left some baby red cabbages to braise on the hob with some garlic, rosemary, mustard and cream, picked some beans then began sorting out dear Heston's recipe for traditional mushroom ketchup with what I had available.
360 g apple cider vinegar
100 g castor sugar
170 g swiss brown
mushrooms, stems discarded, quartered
118 g red wine
3 g mushroom soy
40 g brown onion, finely chopped
1 star anise
2 whole cloves
100 g chicken stock
3 g potato starch
Bring 300 g of apple cider vinegar to a simmer with castor sugar to dissolve.
Pour into a bowl and immerse all mushrooms until soft (about 1 hour).
Combine remaining vinegar with red wine, onion, star anise, cloves, soy and boil to reduce by 2/3rds. Strain.
Make a slurry with a tablespoon of chicken stock and potato starch in a small bowl.
Add all chicken stock, whisking continuously, then temper with a little red wine reduction.
Pour back into pot and whisk until smooth.
Bring to the boil to thicken (keep whisking).
Reduce until it reaches the desired consistency or thin with a little more stock.
Strain the mushrooms from the pickling liquid and stir into the thickened ketchup.