Slow Cooker Sausage Casserole with Side of Mash and Chopped Parsley

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This slow cooker sausage casserole is a great winter pick-me-up. Juicy sausages slow cooked in a rich onion, butter bean and tomato sauce flavoured with thyme. Yum! It can be cooked in 4 hours on low or 8 hours high, making it a perfect mid-week meal that can simmer all day while you work.

Can you put raw sausages in the slow cooker?

Yes, you can most definitely put raw sausages in the slow cooker. However, they will pack in more flavour if seared first.

Searing caramelises the surface which adds a lot of body to the dish. A lot of people believe that searing will also lock the juices into the meat, however, this is not true. So if you are short on time then feel free to skip the pre-sear for the sausages.

The same goes for the onion in this recipe. Pan-frying them first really does add a lot of flavour to the dish. Another thing to note is that it adds more colour to the final result, which is actually pretty important in an otherwise brown and non-colourful dish such as a casserole.

How do you make the sauce thicken in the slow cooker?

To thicken this recipe some flour is added to the onion and briefly cooked before adding to the slow cooker. Tossing the flour in with the onions before adding to the slow cooker will make sure there no raw taste left with the flour. Coating the onions with the flour first will also make sure that it is distributed evenly and you don’t end up with clumps of flour in the sauce.

If you are in a rush and plan to skip the pre-frying of the sausages and the onion then you can mix the flour with an equal amount of water and whisk until you get a smooth consistency. Then mix this into the liquid in the slow cooker and then cook as normal.

You can also use cornflour/cornstarch to thicken slow cooker dishes. You can read some of my top tips for using cornflour in the slow cooker here.

What can you serve this with?

There is nothing better than some good old mashed potato to go with this sausage casserole. The creamy mash is just amazing with the thick sauce from this dish. You can also use other types of potatoes, such as roasted potato or even boiled potato.

Slow Cooker Sausage Casserole Served with Mash on a Plate

Some crusty bread also goes well with this dish, to help mop up all the juices on the plate. If you want to add some extra veg then I highly recommend this roasted tenderstem broccoli.

Can you freeze it?

This casserole is great for freezing. Simply cool before portioning into freezer-proof containers. Store for up to 3 months in the freezer and defrost thoroughly before reheating (leaving it overnight in the fridge is a good idea).

It can be reheated in the oven or in the microwave. You may need to add another splash of water if it’s looking a bit dry. Make sure the sausage is steaming hot all the way through before eating.


You’ll need a few ingredients for this slow cooker sausage casserole:

Slow Cooker Sausage Casserole Ingredients
  • Oil – for frying – an oil with a high smoke point works best (such as canola/rapeseed or grapeseed) but olive oil also works
  • Sausages – I used pork but chicken or beef would also work
  • Onion, sliced – brown or white
  • Plain (all purpose) flour
  • Chopped tinned tomatoes
  • Worcestershire sauce
  • Red wine – optional, you can substitute this with some vegetable stock
  • Dried thyme
  • Garlic, minced or crushed
  • Butterbeans (tinned)

How to make it

First, heat the oil in a frying pan over medium-high heat. When hot add the sausages and cook for around 6-8 minutes, rotating them regularly. When they are browned on all sides then remove from the pan and place in the bottom of the slow cooker.

Next, reduce the heat a little on the pan and add the onion. Cook for around 8 minutes until softened and caramalised. Dust the flour over the onions and cook for a further minute, stirring often. Tip the onions and flour over the top of the sausages in the slow cooker.

Mix together the chopped tomatoes, Worcestershire sauce, red wine, thyme and garlic. Pour over the sausages and then tip the butterbeans on top.

Give everything a quick stir and then set the heat to low for 8 hours, or high for 4 hours.

Recipe Steps

Looking for more great slow cooker meals? You might want to try:

Products that work well for this recipe:

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Slow Cooker Sausage Casserole with Side of Mash and Chopped Parsley

Slow Cooker Sausage Casserole

  • Author: caroline
  • Total Time: 51 minute
  • Yield: 1 1x


This slow cooker sausage casserole is the perfect mid-week pick-me-up. Juicy sausages in a rich tomato and onion sauce. Ideal for cold winter nights.

The default recipe serves one.


Units Scale
  • 1 tsp olive oil
  • 2 uncooked sausages (pork or beef)
  • 200g / 7oz tinned tomatoes
  • 1 clove garlic, crushed
  • 1 tbsp Worcestershire sauce
  • 1 tsp dried thyme
  • 60ml (1/4 cup) red wine
  • 120g / 4.2oz tinned butter beans
  • 1/2 white or brown onion, sliced
  • 2 tbsp plain flour


  1. Heat the oil over medium-high heat in a large frying pan/skillet. Once hot add the sausages and cook for around 6-8 minutes until browned all over. Turn them every few minutes.
  2. While the sausages are cooking mix together the chopped tomatoes, garlic, Worcestershire sauce, red wine and thyme and mix. 
  3. Once the sausages are browned, place them in the slow cooker. Reduce the heat to medium and cook the onions for around 8 minutes, stirring often so they don’t burn. You do want them to caramelise (brown) a little and soften, however. 
  4. Scatter the flour over the onions and stir. Cook for a further minute before tipping the onion and flour mixture into the slow cooker.
  5. Pour the tomato mixture over the sausage and onion and tip over the butter beans. Stir everything together and then cook on low for 8 hours or high for 4 hours. 


  1. If you are using fresh thyme instead of dried then use 1/2 tsp of fresh leaves per person, stripped from the stalks
  2. You can replace the red wine with chicken stock if you prefer
  3. If you are really short on time then you can skip pre-cooking the sausage and onion although the flavour won’t be as rich. If you do this then mix the flour with an equal amount of water and whisk until fully combined then stir into the slow cooker before cooking. 
  4. Leftovers can be frozen for up to 3 months. Defrost before reheating in the microwave or in the oven. You may need to add a splash of water to loosen the sauce if it is too thick. 
  • Prep Time: 20 minutes
  • Cook Time: 4-8 hours
  • Category: Dinner
  • Method: Slow Cooker
  • Cuisine: British


  • Serving Size: 1
  • Calories: 610
  • Fat: 20g
  • Carbohydrates: 62g
  • Protein: 31g

Keywords: slow cooker, dinner, comfort food, indulgent, british, sausages, onion

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