Preheat the oven to 200°C/180°C fan. Peel and chop the parsnip, carrots and turnips into bite-sized pieces. Peel and chop the onion into wedges. Transfer the lot to a baking tray. Drizzle with oil. Add the fresh thyme and salt. Toss. Bake for 25 min. Discard the thyme sprigs.

Meanwhile, peel and chop the potatoes into bite-sized pieces. Add them to a pan of salted boiling water. Cook the potatoes over a medium heat for 15 min or until soft. 

Meanwhile, peel and mince the garlic. Heat a large pot with a lid over a medium heat with a drizzle of vegetable oil. Once hot, add the garlic and tomato paste. Cook for 1 min. Add the chopped tomatoes, bay leaves, marmite, black pepper, smoked paprika, brown sugar, vegetable stock and measured water. Cover and simmer for 15 min.

Once ready,. add the cooked parsnip, carrots, turnips and onions to the tomato sauce. Simmer for 5 min further.

Once soft, drain the potatoes and return them to the pan with the vegan butter. Mash until smooth and season with salt and pepper.

Discard the bay leaves from the stew. Serve the mashed potatoes under the stew. Garnish with the fresh parsley leaves.