Pic of Chestnut, thyme and mushroom casserole with mashed potato

Chestnut, thyme and mushroom casserole with mashed potato

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Vegetarian mains

Chestnut, thyme and mushroom casserole with mashed potato

Main Serves 2 50 min
Chestnuts aren't just for Christmas, they're a great addition to vegetarian dishes all year round. Here we using their nutty sweetness with our chestnut mushrooms in a hearty casserole, with red wine and fresh thyme.

Cook's notes

If you don't have a potato ricer, treat yourself to some new kitchen kit or add one to your next birthday or Christmas list. They make the smoothest mash with little effort, and aren't too expensive to buy. It's fine to use a potato masher, of course, but don't be too over zealous with it, as you can overwork the mash, making it gloopy.


  • 1 onion
  • 1 large or 2 small garlic cloves
  • 1 tsp thyme leaves
  • oil for frying e.g. sunflower or light olive
  • 400g mushrooms
  • 6 cooked chestnuts
  • 1 tsp wholewheat plain flour
  • 1 tbsp tomato purée
  • 75ml red wine
  • 1 tbsp vegetarian Worcester sauce
  • 1 low salt vegetable stock cube
  • 600g potatoes
  • 25g butter
  • splash milk (optional)
  • handful parsley
  • salt and pepper


Prep time: 15 min
Cooking time: 35 min
  • Step 1

    Peel, halve and finely slice the onion. Peel and finely chop or crush 1 large or 2 small garlic cloves. Pick the leaves off enough thyme sprigs so you have 1 good tablespoon worth. Heat 2 tablespoons of oil in a flameproof casserole, one with a lid (or use a saucepan, then transfer to a casserole or baking dish, using foil to cover).
  • Step 2

    Gently fry the onion, stirring now and then, for 10 minutes or until softened. Add a splash of water if it looks like catching at any point. Meanwhile, preheat your oven to 180°C/Gas Mark 4. Wipe the mushrooms clean with a damp piece of kitchen paper or clean cloth. Cut them into quarter's. Break up the chestnuts (they tend to be stuck well to each other!).
  • Step 3

    Once the onion has cooked for 10 minutes, add the garlic, mushrooms, thyme and flour. Increase the heat slightly. Stir-fry for 2-3 minutes, just to soften the mushrooms slightly, and cook the flour out.Add the tomato purée. Stir for 1 minute. Add the wine, Worcester sauce and 300ml water.
  • Step 4

    Crumble in half the stock cube and stir in the chestnuts. Season with salt and pepper. Bring the pan to the boil. If you've used a saucepan, transfer to an ovenproof casserole at this point. Cover whichever pan or dish you're using and cook in the oven for 30 minutes.
  • Step 5

    Check and stir it towards the end, adding a splash more water if needs be. While it cooks, wash, peel and dice the potatoes into 2-3cm chunks. Put them in a pan of cold water. Season well with salt and bring the pan to the boil. Cook for 10-12 minutes or so, until the potatoes are soft when pierced with a sharp knife. Once cooked, drain into a colander. Leave in the colander for 2 minutes to allow excess water to evaporate.
  • Step 6

    Mash in the same saucepan with the butter, salt and pepper to season, and a splash of milk from your fridge too, if you like. The mash can be kept and gently reheated to serve with the casserole. Wash, shake dry and roughly chop the parsley.
  • Step 7

    Once the casserole is ready, stir in the parsley, check the seasoning and serve with the mash.

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