Place dry porcini or shiitake in a small bowl and pour over boiling water to cover. Set aside.

In a large non-stick frypan, add a thin layer of water (not oil) and fresh mushrooms. Sprinkle with a few pinches of salt and braise mushrooms over medium-high heat, lifting and turning with a spatula, until they have given up their water, the pan is almost dry and the mushrooms are starting to shrivel.

Add ½ tbspn of the oil and saute mushrooms until caramelised. Set aside.

In a large heavy-based pot add remaining oil plus onions and leeks. Stirring regularly, saute over medium-high heat until softened, translucent and just colouring at the edges, then add carrot, garlic and celery.

Saute until vegetables begin to caramelise, then add tomato paste. Cook another few minutes, stirring well.

Add lentils and caramelised mushrooms, stirring well to coat, then add wine, porcinis and their soaking water, chicken or vegetable stock and all herbs except parsley. Season well with freshly ground black pepper and bring to the boil over medium-high heat.

Reduce heat and simmer until vegetables are tender and lentils are just softened and good to eat but not yet splitting or mushy. Stir regularly to prevent the braise catching.

When cooked, season well with salt and more pepper to taste, remove bay leaves, mix in parsley, then tip your braise into a large colander set over the frypan you used for your mushrooms and allow to drain.

Bring the juice in the frypan to a boil and reduce until thick enough to be spread on a silicone- or baking paper-lined dehydrator tray without running off the edges.

Spread thickened sauce onto a lined tray(s).

Place one serve of lentils and vegetables in a bowl and weigh: this is your ONE SERVE WET WEIGHT A. Transfer this serve to a dehydrator tray and mark it with a teaspoon.

Spread the rest of the drained lentil and veg mix onto dehydrator trays.

Dehydrate at 52C (125F) or, if you’ve used chicken stock, at 71C (160F), until completely dry.

Partway through, stir veg and lentils to separate any clumps. Peel sauce from silicone and invert onto mesh to continue drying.

When dry, weigh your marked tray: this is ONE SERVE DRY WEIGHT B.

Place it plus all the other dry lentils and veg into a large bowl.

Break up the sauce into shards and powder in a spice grinder, then dry powder on a silicone lined tray for another ten minutes to condition. Place powder in a bowl.

Into each vac seal bag place 2 x B (ie two serves) powder, distributed equally between bags. Vacuum seal.

On the outside write date, and water (W) needed to rehydrate the two serves ie 2A - 2B = W+. You might need a little extra(+) for the powder.

In Camp: Bring W+ water to the boil. Carefully slit top of vac seal bag and pour in water. Close bag and put into a cosy for 20-25 minutes.