Lentil shepherd's pie

Ingredients

• 3 tbspolive oil
• 2onions, finely diced
• 3carrots, finely diced
• 3 stickcelery, finely diced
• 3 clovegarlic, crushed
• 8 3/4 ozchestnut mushrooms, finely chopped
• 3 tbsptomato paste
• 10 1/2 ozgreen lentils, rinsed
• 3 3/4 cupsvegetable stock
• 6 sprigfresh thyme, leaves picked
• 5 1/4 ozfrozen peas
• 2.6 lbfloury potatoes, peeled and cut into even chunks
• 2 3/4 ozsalted butter
• 1/2 cupwhole milk, warmed
• 2 3/4 ozmature cheddar, grated
• 3/4 tbspsea salt
• 1 tspblack pepper

Method

1. 1

   Heat the oil in a wide pan and cook the onions, carrots and celery with a teaspoon of the salt for 12 minutes. Add the garlic and mushrooms and cook for a further 8 minutes, until the mushrooms have given up their water and started to brown. Stir in the tomato paste for 2 minutes.

2. 2

   Add the lentils, stock and thyme, bring to the boil, then simmer uncovered for 35 minutes until the lentils are tender and the mixture is thick rather than soupy. Stir in the peas and season.

3. 3

   Boil the potatoes in salted water for 20 minutes until tender, drain them, then return them to the empty hot pan for a minute, shaking, until the steam stops. Mash with the butter, warm milk and the rest of the salt.

4. 4

   Heat the oven to 400°F. Spoon the filling into a large baking dish, spread the mash over in an even layer and rough the surface up with a fork. Scatter the cheddar over and bake for 30 minutes, until browned and bubbling at the edges.