Cook the lentils if you are not using pre-cooked lentils.

Preheat the oven to 200°C/180°C fan. Grease the sides of a 20–23m cake tin with some vegan butter and line the bottom with baking parchment.

In a small bowl, mix the ground flaxseed with 3 tablespoons of water. Set aside.

Roughly chop the mushrooms and pick the leaves off the thyme sprigs.

Toast the walnuts in a dry frying pan over a medium-low heat for about 6 minutes, then finely chop or blitz in a food processor to a coarse texture. Set aside.

Mince the garlic and finely dice the shallots. Melt the butter in a saucepan over a medium heat. Add the shallots and cook for 7–8 minutes until translucent, then add the garlic and sauté for 2 minutes more.

Add the mushrooms and thyme and increase the heat to medium-high. Sweat them down for about 15 minutes until all the moisture has evaporated. You might need to split the mixture between two pans for this, as you don’t want to overcrowd the mushrooms in one pan. They need plenty of space to caramelise.

Add the balsamic vinegar and soy sauce, and stir for a few minutes until they evaporate. Season well.

Add the flaxseed mixture, along with the walnuts, lentils and 2 tablespoons of the cream cheese. Check the seasoning

Spoon the mushroom mixture into the prepared tin and use the back of a spoon to even out the surface. Pop the cake tin onto a baking tray, as it may leak. Bake for 30 minutes until golden brown on top.

While the mushroom bake is in the oven, peel and thinly slice the celeriac and beetroot. Use a mandoline if you have one, or a very sharp knife. Try to slice them about 3mm thin.

Put the celeriac and beetroot slices into two separate roasting trays. Season well and drizzle with olive oil, tossing to make sure that each slice is evenly coated. Cover tightly with foil and roast for 20 minutes until soft and supple enough to crumple.

In a small bowl, mix together the miso, mayonnaise and mustard and a squeeze of lemon juice, until smooth.

In a separate bowl, mix the rest of the cream cheese with 4 teaspoons of the miso mayo mustard and a squeeze of lemon juice. Taste and add a little more mustard or lemon if you like.

When the mushroom bake is ready, set aside to cool for 15 minutes before removing from the cake tin and leave to cool completely. Once the bake has cooled, spread the cream cheese mixture over the top with the back of a spoon, taking care not to scrape off the top of the bake.

Next, scrunch the pieces of celeriac and beetroot and place them one by one on to the cream cheese. Arrange them close to one another so that they hold their shape. Continue until you have covered the whole top of the bake.

Finally, drizzle the miso mayo mustard all over the top, then finish with a sprinkle of pomegranate seeds, if you like, and parsley or dill, and serve.