1kg(just over 2 lbs) of floury potatoesI used Maris Piper, peeled and cut into quarters
50g(3½ tbsp) butterI use salted butter
150ml(⅔ of a cup) of semi skimmed milk
½tspfreshly ground black pepper
40g(⅓ of a cup) of mature (sharp) cheddargrated using the large grater side of a box grater.
To make the filling
Heat a tablespoon of oil in a large sauté pan.Add the chopped onion, celery and carrot along with a pinch of salt.Cook over low to medium heat for about 20 minutes, stirring often to avoid the onion burning.
Once the onion has softened add the garlic and cook for a minute.Then add half a tablespoon of butter, all the chopped mushrooms, a pinch of salt and a small pinch of freshly ground black pepper.Cook for about 10 minutes, until the mushrooms release their juices. Stir often.
Add the chopped parsnips and cook for a few minutes.Then add one heaped tablespoon of tomato puree (paste) and one heaped tablespoon of plain (all-purpose) flour. Stir the paste and flour into the vegetables and cook for a minute or two.
Now pour in the stock one ladle at a time, stirring the stock into the vegetable mixture each time. The sauce will be thick to start off then will end up being slightly thin.Add all the lentils to the stock and stir well.
Stir in one tablespoon of Henderson's relish, two tablespoons of soy sauce and one heaped tablespoon of red currant jelly.Season with salt and freshly ground black pepper.Add the thyme sprigs and bay leaves.Reduce the heat and simmer uncovered for about 20 minutes. Stir often to avoid sticking at the bottom of the pan.The filling is done when the sauce is nice and thick.After 20 minutes transfer to a large casserole dish and stir in the frozen peas.
To make the mashed potato topping
Put the quartered potatoes into a saucepan. Cover with cold water and add a good pinch of salt.Bring the water to a boil then reduce to a fast simmer.Cook until the potatoes are tender. Test with a knife, the knife should go through the potato easily and should fall off the knife.Drain the potatoes, return the cooked potatoes to the saucepan and put them back on the heat for a minute to dry out.
Mash the potatoes using a potato masher or ricer. They should be lump-free.
Add the milk and butter to a small saucepan and heat over medium heat until the butter has melted.Pour the warm milk and melted butter into the mashed potatoes. Do this in stages, about a quarter at a time. Beating the liquid into potatoes with a wooden spoon.Once all the milk and butter has been added and you have a smooth mash season with sea salt and black pepper.
To assemble the cottage pie
After you have added the peas to the vegetable mixture, use the back of a tablespoon to make sure the mixture is evenly spread out in the casserole dish.
Add one heaped spoon of the mash to the vegetable mixture.Start in one corner and keep adding the mashed potatoes until they fully cover the vegetable mixture.Use a fork to spread the potatoes evenly over the vegetable mixture. You can make a criss-cross design with the fork if you like.
Top with the grated cheese.
Place the pie on a baking tray then place it on the middle tray in the oven.Bake in a preheated oven at 170°C (335°F) Fan/ 190°C (370°F) conventional oven.The cottage pie is cooked once the topping is a light golden brown and the liquid is bubbling up at the edges.Leave to cool slightly before serving.Add a sprinkling of chopped parsley as a garnish if you like.
Casserole dish - I used a 26cm/10-inch square casserole dish and it was 6 cm/2 and a half inches deep.
Lentils - I use pre-cooked Puy lentils for this dish, you can use canned brown or green lentils if you prefer.
Mushrooms - Chestnut mushrooms are similar to crimini mushrooms and generally have more flavour. You can use white mushrooms if you like.
Potatoes - floury potatoes are best for the mash, I used Maris Piper, Yukon Gold is very good too.
Freezing - this dish can be frozen, leave it to cool, don't add the cheese and don't bake it. Cover it and place it in the freezer. Use within 3 months. Defrost in the fridge overnight before reheating. It is best to reheat this, covered with foil, in the oven. Microwaving will dry out the cottage pie.
Nutritional Information - is calculated using an online tool and is approximate. It is based on one serving of 6.
Weights and measurements - For US readers, I use Cuisipro measuring cups and spoons, and a Pyrex measuring jug for liquids. These are the industry standard. Cup/spoon volumes can differ from brand to brand, for accuracy, I recommend weighing all ingredients if possible for best results.