How to make a Slow Cooker Lasagne

Making Slow Cooker Lasagne was a massive psychological breakthrough for me with using the slow cooker. I’d go as far as to say it transformed my relationship with this particular kitchen appliance.

Like most of us probably, my memories of slow cooker food were the stews of my childhood. Brownish grey, soupy things that made the house smell meaty and warm.

An Easy Life?

As an adult I’d tentatively had a go at making food in the slow cooker – usually stews – and always come away frustrated by the experience.

Slow cookers had been sold to me as something that would make my life easier. Yet prep took forever and I genuinely couldn’t understand where the advantage was to cooking in the slow cooker if you also still had to fry onions and veg and/or brown the meat before it went it.

5p an hour to run

But times are tight and with studies revealing that slow cookers cost about 5p an hour to run and ovens more than £1 I decided to renew my slow cooker efforts. However I was determined to take my cooking in a different direction this time – away from stews.

So when a friend suggested I have a go at a slow cooker lasagne I was somewhat skeptical but game.

Early Prep

I did the prep first thing Saturday morning, getting my meaty sauce all fried up and ready on the hob (as per any standard lasagne making – see method below for more details). We then cracked on with other jobs, and it was just after lunch that I made the sauce (on the hob, as usual),  before layering up the lasagne in the slow cooker.

The rest of the afternoon was spent having friends over for a Christmas card making afternoon. As you can imagine the house – and specifically the table in the kitchen which was our art studio for the afternoon, rapidly deteriorated into a mix of glitter and glue and cut up bits of cards and paper and general chaos. It was a huge amount of fun BUT when our friends left and I’d tidied round, it was pretty much time for dinner.

Delicious Dinner!

THIS was my moment of revelation with the slow cooker – I’d done all the hard work earlier in the day which meant a quick tidy round, bunging the oven on briefly for the accompanying garlic bread and to crisp up the top of the lasagne and boom, 20 minutes later we were all sitting down to a scrumptious meal without the usual sense of ‘cooking in a hurry’.

I have to say – as did my husband and my children – it’s probably the best lasagne I have ever made! The flavours were rich and deep and pretty much everyone went back in for seconds. That did mean there wasn’t as much to box up and freeze for another occasion as I’d hoped for (though I did squeeze out another two small portions for the kids) but we all had a delicious meal.

To make a slow cooker lasagne you will need:

A slow cooker!


2 onions, finely chopped

2 x  celery sticks grated

3 x carrots grated

2 garlic cloves, pressed

400g lean (5% fat) mince beef

400g can chopped tomatoes

2 tbsp red pesto

2 tsp vegetable bouillon

1 tbsp fresh thyme leaves

lasagne sheets

For the sauce you will need:

400ml milk

50g flour

1 bay leaf

15g grated cheese


Using a large frying pan or cookpot, first fry the onions, grated carrots and celery in a dash of oil on the hob on a medium heat for a few minutes, until the onions become translucent and your kitchen begins to smell delicious. Then add in the crushed garlic cloves for a minute before popping the mince into the pan. Cook till the mince is browned all over.

Then add the can of chopped tomatoes, the tomato pesto, vegetable bouillon and the fresh thyme leaves. Make sure everything is well mixed and wait till it comes to a bubbling simmer again.

At this point you can take the mince sauce off the heat and leave till you’re ready to start building the lasagne in the slow cooker.

Next, make the white sauce by tipping the flour, the milk and the bay leaf into a pan and whisk like crazy whilst applying heat to the sauce. It should thicken in a few minutes (broadly speaking, just before you feel like your arm is about to drop off!). Once it’s thick and saucy, fish the bay leaf out and add in the cheese.

Now you’re ready to begin building the lasagne. First put a layer of the meat sauce on the bottom of the slow cooker dish, then add a layer of lasagne boards, probably cracking and breaking a few in order to make sure the whole surface area of the meat is covered. Then add another layer of meat, another layer of lasagne boards and so on. When you are close to the top of the slow cooker pot add a final layer of lasagne boards and then cover them with the cheese sauce you’ve just made.

Pop the slow cooker on LOW and cook for three hours.

Energy cost saving

Bear in mind you’d probably cook your oven lasagne for about 40 minutes in the oven – costing you energy wise about 40 – 45p, the same dish in the slow cooker cooks on low for 3 hours – costing you a mere 15p. We did put the oven on for garlic bread (15 minutes) and so used that time to also crisp up the top of the slow cooker lasagne. This equates to an additional 15p roughly in energy costs but still 10 – 15p cheaper than using the oven.

Cost of Ingredients

Slow cooker lasagne (Serves 6)

Cost 2 onions, finely chopped 0.20

2 x  celery sticks grated 0.10

3 x carrots grated 0.17

2 garlic cloves, pressed 0.04

400g lean (3% fat) mince beef 3.19

400g can chopped tomatoes 0.32

2 tbsp red pesto 0.15

2 tsp vegetable bouillon 0.16

1 tbsp fresh thyme leaves 0.13

lasagne sheets 0.40

For the sauce

400ml milk 0.29

50g flour 0.02

1 bay leaf 0.07

15g grated cheese 0.10

Total cost of ingredients £5.34 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.


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

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