How to make Slow Cooker Cottage Pie

Having discovered, through making the Slow Cooker Lasagne, the joy of making dishes I’d traditionally think of as oven bakes in the slow cooker I decided to keep going down this track.

Having reframed my thinking about slow cookers, away from the notion that they can save me time in the cooking process, towards a recognition that their real value lies in a more efficient form of oven cooking, Slow Cooker Cottage pie felt like the obvious next step for me.

Low-cost healthy comfort food

The recipe I made was loosely based on this one, with a few small amends on my part. One of the things I LOVED about this meal was that it was really cost effective – working out at about 90p per person based on current Aldi grocery costs. It served 4 quite easily and I’ve put a portion in the freezer that could either be one for the kids to share or a single adult meal. I find I can make these sort of meals go further if I also serve a vat of peas or sweetcorn or green beans with them – and these are always items I have in the freezer anyhow too.

Slow Cooker Cottage Pie was also a low-fat version of this traditional winter comfort food and it packed in extra veggies. I added celery to mine, because, why not!? The more veggies we can eat in any one meal the better! 

Lentils vs meat

Replacing a chunk of the usual meat content with a can of green lentils was also an ace idea. I’m always looking for new (tasty) ways to incorporate lentils into meals and to find ways in which to reduce or exclude meat entirely from the food we eat, but still gain the approval from my meat-eating family – so this was a double winner for me. The lentils both cut the overall cost of the meal and boosted the health value.

I grated the veg into it, something I’ve been doing for a few years now to ‘hide’ some of the vegetable content from my kids and in the end I actually used full-fat crème fraiche because that was what I had in. I also flashed the cottage pie under the grill at the very end for a few minutes to get a bit more of a crunch to the topping. It was super easy to make and hugely popular in the house so has now been added to my staple food offering

For Slow Cooker Cottage Pie you will need…

A slow cooker!


1 tbsp olive oil

1 onion, finely chopped

3-4 thyme sprigs

2 carrots, grated

2 celery sticks, grated

250g lean (5%) mince beef

1 tbsp plain flour

1 tbsp tomato purée

400g can lentils

1 tsp Worcestershire sauce

For the topping

650g potatoes, peeled and cut into chunks

250g sweet potatoes, peeled and cut into chunks

2 tbsp half-fat crème fraiche


As is the case with all the slow cooker meals I’ve been exploring, the cooking methodology is exactly the same as it would be if you were making the dish to then cook in the oven.

Start by getting your potatoes and sweet potatoes cooking in a pan of lightly salted water. You want to have them simmering for about 15 minutes, until they are soft enough to mash.

Once the potatoes are on,  pour some oil into a large frying pan or cookpot and gently fry the onions and the thyme for a few minutes, before adding the rest of the veg and frying till they are softened and the onions translucent.

Next add the mince and cook until browned all over. Add the flour and mix in well with the mince before tipping in the tomato puree, drained and rinsed lentils and a half can of water. Pop in the Worcestershire sauce and season to taste.

Scrape everything out of the pan and into the slow cooker. Drain the pan of potatoes and add the crème fraiche to the mix, then mash like crazy!

Pop the mash potato mix on top of the meat and lentils in the slow cooker and cook on LOW for 5 hours.

Before serving, flash the cottage pie under the grill for a few minutes to crisp up the top. Serve and watch everyone around the table admire your cooking prowess!

Energy cost saving

You generally oven cook a cottage pie for around 45 minutes at 180c in a conventional oven, which costs somewhere in the region of 45-50p. Making the same dish and cooking it in the slow cooker for five hours costs more like 25p which is nearly a 50% energy saving, based on energy estimates that suggest running a slow cooker costs 5p per hour, vs an oven at around £1 per hour.

Slow cooker cottage pie (serves 4) Costing based on Aldi prices at 11th Dec 2022


1 tbsp olive oil

1 onion, finely chopped 0.10

3-4 thyme sprigs 0.13

2 carrots, finely diced 0.11

250g lean (5%) mince lamb or beef 1.99

1 tbsp plain flour 0.02

1 tbsp tomato purée 0.03

400g can lentils, or white beans 0.49

1 tsp Worcestershire sauce 0.03

For the topping

650g potatoes, peeled and cut into chunks 0.31

250g sweet potatoes, peeled and cut into chunks 0.25

2 tbsp half-fat crème fraîche 0.11

Total cost £3.56

Price per portion 0.89

Total cost of ingredients £3.56 or 89p per portion, based on Aldi pricing and are correct as at Dec 11th 2022.

This recipe was created by Rebecca Megson-Smith. A writer, writing coach and feminist, fuelled by books, tea and time by the sea. You can find her on her website, Instagram @ridleywrites and lurking on Twitter @ridleywrites.

Also check out Rebecca’s slow cooker lasagne recipe.


More to explore

Comparing Energy Usage and Costs – Cooking Bolognese and Lasagna in different ways

Octopus Energy recently challenged me to investigate the costs of cooking various recipes using different devices to understand the difference in energy


Lynn Beattie

Aka Mrs MummyPenny

Personal Finance Expert

I write about personal finance made simple, lifestyle choices that will save you time and money, as well as products and services that offer great value.

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