This Vegetarian cottage pie, with a cheesy sweet potato and lentil, is hearty, comforting and perfect for a meat-free dinner.
A rich lentil and vegetable filling is topped with creamy sweet potato mash, plenty of mozzarella and a little black pepper, then baked until the cheese is golden and bubbling.
I first made this recipe more than six years ago using frozen sweet potato and frozen mixed vegetables. For this updated version, I use fresh sweet potato for the topping, while keeping frozen mixed vegetables because they make this such an easy and budget-friendly family meal.
It is simple, satisfying and one of those dinners that feels properly comforting without needing meat.

Sweet potato gives this cottage pie a completely different character.
It is naturally creamy when mashed and has a gentle sweetness that works beautifully with the savoury lentil and tomato filling underneath.
The sweet potato also pairs really well with paprika, herbs and melted mozzarella.
I like leaving the mash slightly rustic rather than making it completely smooth.
The filling is deliberately simple.
Onion, garlic, bay leaves, paprika and dried herbs form the base, followed by chopped tomatoes, vegetable stock, soy sauce, lentils and mixed vegetables.
The soy sauce adds extra savoury depth without changing the flavour of the dish too much.
I use canned lentils because they make the recipe incredibly quick. Just drain and rinse them before adding them to the filling.
Absolutely.
This is one recipe where I think frozen mixed vegetables are genuinely useful rather than simply a shortcut.
They are affordable, convenient and you can add them straight from the freezer.
A standard mix containing vegetables such as carrots, peas, green beans and sweetcorn works beautifully.
You can use fresh vegetables instead if you prefer, but there is no need to make this recipe more complicated than it needs to be.

Before adding the sweet potato topping, let the lentil and vegetable mixture simmer until it is fairly thick.
You do not want a lot of loose liquid sitting underneath the mash.
If the filling looks watery, leave it uncovered for a few extra minutes and allow some of the liquid to reduce.
This gives you a much better cottage pie once it comes out of the oven.
Peel the sweet potatoes and cut them into evenly sized chunks.
Place them in a pot of salted water and bring to the boil.
Cook for approximately 15 to 20 minutes, or until completely tender.
Drain the sweet potatoes thoroughly.
Return them to the hot pot for a minute or two so that some of the excess steam can escape.
This helps prevent watery mash.
Add salt, black pepper and dried Italian herbs.
Mash until mostly smooth.
It is perfectly fine to leave a little texture.
Set aside while you prepare the filling.
Preheat the oven to 200°C.
Heat the oil in a large ovenproof pan or casserole over medium heat.
Add the chopped onion and cook for approximately 5 minutes until softened.
Add the crushed garlic and bay leaves.
Cook briefly until fragrant.
Add the paprika and dried Italian herbs and stir through.
Add the chopped tomatoes and crumble in the vegetable stock cube.
Add the soy sauce and mix well.
Allow the mixture to simmer for about 5 minutes.
Add the drained lentils and frozen mixed vegetables.
Season with salt and black pepper.
Mix well, cover and simmer for approximately 5 minutes.
Remove the lid and allow the filling to reduce a little if it still looks too wet.
Remove the pan from the heat.
Spoon the sweet potato mash over the lentil filling and gently spread it into an even layer.
Scatter over the grated mozzarella.
Finish with a little black pepper and an extra sprinkle of dried Italian herbs.
Place the ovenproof pan in the oven and bake for approximately 20 to 25 minutes until the filling is bubbling and the cheese is melted and golden.
Allow the cottage pie to stand for 5 to 10 minutes before serving.
It is very tempting to spoon it straight out of the oven, especially when the cheese is bubbling.
But giving the cottage pie a few minutes to rest helps the filling settle and makes it much easier to serve.
Five to ten minutes is plenty.

Yes.
You can prepare the lentil filling and sweet potato topping ahead of time.
Assemble the cottage pie, cover and refrigerate until you are ready to bake.
If it is going into the oven straight from the fridge, allow a little extra baking time.
Yes.
Allow the cooked cottage pie to cool completely before freezing.
You can freeze the whole dish or divide it into individual portions.
Thaw overnight in the fridge before reheating until piping hot.
If you prefer a more traditional cottage pie topping, replace the sweet potato with regular mashed potato.
Finely chopped mushrooms are a lovely addition to the lentil filling and give it even more savoury flavour.
Stir baby spinach through the filling just before adding the topping.
Add chilli flakes or a little chopped fresh chilli to the filling.
Replace some or all of the mozzarella with mature cheddar if you want a stronger cheese flavour.

This sweet potato and lentil cottage pie is substantial enough to serve on its own.
If you want something alongside it, keep it simple with:
I love vegetarian recipes like this because they do not feel as though anything is missing.
The lentils make the filling hearty, the vegetables give it colour and texture and the sweet potato and melted cheese turn it into proper comfort food.
It is affordable, simple to prepare and perfect for those days when you want something warm and satisfying.
And if dinner only leaves you with two dishes to wash afterwards, that is a win too.
A hearty vegetarian cottage pie with lentils, mixed vegetables and a cheesy sweet potato topping. An easy, budget-friendly meat-free dinner for the whole family.
SWEET POTATO:
You will need approximately 900 g to 1 kg whole sweet potato to yield around 750 g once peeled and trimmed.
LENTILS:
Canned lentils make this recipe quick and easy. Drain and rinse them well before using.
FROZEN VEGETABLES:
A standard mixed vegetable blend works perfectly. Add directly from frozen.
SOY SAUCE:
Soy sauce adds savoury depth to the lentil filling.
FILLING:
Make sure the filling is fairly thick before adding the sweet potato mash. If it looks watery, simmer uncovered for a few extra minutes.
CHEESE:
Mozzarella gives you a lovely golden, melted topping. Cheddar can also be used for a stronger flavour.
MAKE AHEAD:
Assemble the cottage pie, cover and refrigerate until needed. Add a little extra baking time if cooking directly from chilled.
FREEZING:
Cool completely before freezing. Thaw overnight in the fridge before reheating thoroughly.