Lentil and Mushroom Cottage Pie with Sweet Potato Mash

Ingredients

• 🍠Sweet Potato, peeled and cut into chunks900 g
• 🧈Salted Butter, for the mash30 g
• 🥣Plain Greek Yogurt, for the mash60 g
• 🧂Sea Salt (fine), for seasoning the mash and fillingto taste
• 🧂Black Pepper (ground), for seasoning the mash and fillingto taste
• 🫒Extra Virgin Olive Oil, for the filling2 tbsp
• 🧅Yellow Onion, finely diced1 onion
• 🥕Carrot, peeled and finely diced2 carrot
• 🥬Celery, finely diced2 stalk
• 🧄Garlic, minced3 clove
• 🍄Cremini Mushrooms, cleaned and finely chopped300 g
• 🥫Tomato Paste2 tbsp
• 🫘Brown Lentils, rinsed220 g
• 🥫Crushed Tomatoes400 g
• 💧Water, plus a little extra if needed350 ml
• 🌿Dried Thyme1 tsp
• 🌿Dried Rosemary1 tsp
• 🌿Bay Leaves1 leaf
• 🫙Apple Cider Vinegar1 tbsp
• 🌿Flat-Leaf Parsley, finely chopped2 tbsp

Contains Celery, Dairy, Garlic, Mustard, Onion, Sulphites. AI-generated, checked against common allergens; always check labels.

Method

1. 1

   Peel the sweet potatoes

   Peel the Sweet Potato on a chopping board, then cut it into even chunks about the size of a walnut so it cooks through at the same rate. Keep the pieces neat rather than ragged; if the chunks are very uneven, the small ones will collapse before the larger ones soften.

   8 min
2. 2

   Boil the sweet potato

   Put the Sweet Potato into a large saucepan and cover it with Water, then set it over high heat and bring it to a lively boil. Let it cook for about 15 minutes until the pieces are completely tender at the centre and the edges start to fray; if the water drops too low, add a splash more so nothing catches on the base.

   15 min
3. 3

   Dice the vegetables

   Finely dice the Yellow Onion, Carrot and Celery on a chopping board, and mince the Garlic Cloves so they disappear into the filling. Keep the dice small and even; if the vegetables are chunky, they stay separate instead of melting into a cohesive pie filling.

   10 min
4. 4

   Clean the mushrooms

   Wipe the Cremini Mushrooms clean and chop them finely on the chopping board so they cook down into a dense, savoury layer instead of sitting in big pieces. If any pieces look damp or muddy, trim that bit away rather than rinsing them under water, which makes them steam instead of brown.

   5 min
5. 5

   Mash the sweet potato

   Drain the Sweet Potato well, return it to the warm large saucepan and mash it until smooth before stirring in the Salted Butter and Plain Greek Yogurt. Season with the Sea Salt and Black Pepper, then beat it briefly until the mash is glossy and fluffy; if it seems wet, keep mashing over the residual heat for a minute so steam escapes.

   5 min
6. 6

   Soften the base

   Heat the Extra Virgin Olive Oil in a large saucepan over medium heat until it shimmers, then add the Yellow Onion, Carrot and Celery with a pinch of the Sea Salt. Stir steadily for about 8 minutes until the vegetables look glossy, the onion turns translucent and the carrot edges start to soften; if they start sticking, lower the heat a little and keep them moving.

   8 min
7. 7

   Cook the mushrooms

   Add the Cremini Mushrooms and Garlic Cloves to the large saucepan and stir them through the softened vegetables over medium-high heat for about 5 minutes. Keep them moving until the mushrooms shrink, give off a little steam, and their surfaces go from pale and spongy to darker and glossy; if the pan looks dry, the mushrooms need a minute longer before they start colouring.

   5 min
8. 8

   Build the filling

   Stir in the Tomato Paste and cook it for about 1 minute until it darkens to a brick-red sheen, then add the Brown Lentils, Crushed Tomatoes, Water, Dried Thyme, Dried Rosemary and Bay Leaf. Bring the mixture to a steady simmer over medium heat, stirring to lift up anything stuck on the base, and keep it bubbling gently until the lentils are tender and the sauce is thick rather than soupy; if it looks too tight, splash in a little more Water.

   15 min
9. 9

   Finish the seasoning

   Take the large saucepan off the heat and stir in the Apple Cider Vinegar, Flat-Leaf Parsley, Black Pepper and the remaining Sea Salt until everything smells brighter and the herbs are evenly distributed. Taste a spoonful and adjust the seasoning if needed; the sauce should feel rounded, savoury and lively rather than sharp, and the bay leaf should be easy to spot so you can fish it out next.

   2 min
10. 10

    Top the pie

    Spoon the filling into a large ovenproof dish and spread it into an even layer, then spoon the sweet potato mash on top and nudge it to the edges so it seals the filling in. Rough up the surface with the back of a spoon to create ridges; those peaks turn bronzed in the oven, while a very smooth top stays paler.

    5 min
11. 11

    Bake until bronzed

    Bake the pie in the large ovenproof dish at 200°C for about 20 minutes until the filling is bubbling at the edges and the sweet potato peaks are lightly bronzed. If you want a deeper top, let it go a few minutes longer until the ridges darken to amber, but watch closely so the edges do not dry out.

    20 min
12. 12

    Set before serving

    Let the pie stand for about 10 minutes before cutting so the filling settles and the slices hold together. The top should still be steaming, but the edges will relax from very loose to neatly set; if you cut too soon, the filling will run and the layers will blur.

    10 min

Nutrition per serving