Caramelised sausage and onion bake with colcannon topping

This easy sausage and mash casserole is a rustic-looking dish, with the gravy soaking up around the potatoes on the edges, but in spite of that, it's no less tasty.

It is made with sausages, cooked in a rich onion and mushroom gravy, topped with a cheesy colcannon-style mash, and oven-baked until golden.

Even though this is a super-easy dish to make, it does take a little time, because there are a few different components that need your attention:

• Fry the sausages and make the onion and mushroom gravy.
• Cook the colcannon topping.
• Assemble the dish and bake it for 30 minutes.

I've tried to streamline everything to make this easy family dinner as simple as possible so that you can cook most of the elements at the same time. Follow the instructions in the recipe card or read the rest of the post for more details.

This recipe is similar to my sausage cottage pie recipe, but I've added mushrooms for extra goodness, changed the seasoning slightly, and used a tasty colcannon-style mash for the topping.

• Economical. A packet of sausages doesn't cost the earth, and beyond that, it's just vegetables and gravy.
• Family-friendly. Because honestly, who doesn't love sausage and mash?
• Something different. Even though this is just plain old sausage and mash, the way in which it's presented makes it feel a bit more special.
• Versatile. You can use different flavoured sausages and swap the vegetables in the mash depending on what you have available.
• Great for leftovers. It reheats really well the next day - I know this because I made it yesterday and we're having the leftovers for supper again tonight!

Ingredients

**This is just an overview to explain why I used a particular ingredient. You can find the exact ingredient measurements on the printable recipe card at the end of this post.**

Casserole

• Sausages. Get a good quality meaty sausage - it will make all the difference. I used Sainsbury's Taste the Difference Caramelised Red Onion Sausages. I like them because they are quite meaty and don't have too much fat in them. Use your own favourite sausages! You should allow 2 to 3 sausages per person.
• Onions. These are white onions (you may know them as yellow or brown onions). They should be peeled and thinly sliced. You could substitute with red onions.
• Mushrooms. Cremini (chestnut) or firm white mushrooms are best. They should be wiped with a damp towel to remove bits of grit or dirt and sliced. Portobello mushrooms would work as well
• Gravy granules. I would normally use flour and stock to thicken the gravy, and you're perfectly fine to do that. I just thought for a change I'd use gravy granules and water. It sped up the cooking process, and it worked well.

Cheesy mash

• Potatoes. These should be brought to the boil in a pan of cold salted water, and boiled until they have softened sufficiently to mash - normally about 10 minutes.
• Leeks. I sliced 2 leeks lengthwise, rinsed them under cold water to remove any bits of dirt, and sliced them into semi-circles. Leeks have a lovely mild oniony flavour, so your best substitute would be shallots. Failing that, you could use red or white onions.
• Cabbage. This is white cabbage, which was finely sliced and cooked with the leeks. If you don't like cabbage, consider increasing the amount of potatoes, or use a different vegetable such as finely chopped green beans, spinach or grated carrots.
• Cheese. This is just stock standard grated cheddar cheese. You can use any cheese that grates and melts well. Mozzarella on its own might be a bit mild; consider combining it with a sharper cheese.

Not pictured

• Oil. A splash of vegetable or olive oil for browning the sausages.
• Butter. For softening the leeks. I like to use unsalted butter so I can control the amount of salt in the dish. You could use salted butter instead.
• Dried thyme. This is optional, but I love thyme and always add it when I'm cooking with mushrooms.

How to make this colcannon-topped sausage casserole

These instructions are intended to help you organise your time when making the dish. These are the steps in a nutshell.

• Prepare the veg. Peel the potatoes, and slice the leeks and cabbage. Peel and slice the onions, and wipe and slice the mushrooms.
• Get the potatoes on to boil and saute the leeks and onions.
• Mash the cooked vegetables together with cheese.
• While the vegetables are cooking, you can fry the sausages and make a start on the mushroom and onion gravy.
• Finish off the gravy.
• Assemble the dish and get it in the oven.

So let's look at it in more detail:

Leek and cabbage colcannon mash

Step 1: Place the potatoes into a pan of cold, lightly salted water and bring to a boil. Boil for about 10 minutes, or until the potatoes are soft enough to mash. Drain the water and set the potatoes aside.

Step 2: Melt butter in a saucepan over moderate heat and saute the leeks for 3 to 4 minutes, stirring to prevent them from burning.

Step 3: Add ¼ cup (4 tablespoons) of water to the leeks and add the sliced cabbage. Cover the pan with a lid and leave on moderate heat for about 10 minutes or until the cabbage is soft enough to mash. There should be no liquid left in the pan; if there is, you can drain most of it away.

Step 4: Place the cooked potatoes, leeks and cabbage in a large bowl and add the grated cheese. Mash until well combined, then taste for seasoning and adjust if necessary. Set the mash aside until you are ready to spread it over the sausages and gravy.

Sausages and gravy

Step 5: Remove the sausages from their skins and form them into balls. I made three balls from each sausage.

Step 6: Heat a splash of oil in a frying pan over moderate heat and brown the sausage balls for 2 to 3 minutes, turning with a spatula to brown on all sides.

Step 7: Transfer the browned sausage balls to a casserole dish. Note, they don't need to be cooked all the way through - they will finish cooking in the oven.

Step 8: Add the mushrooms and onions to the same pan. There should be enough oil left over from frying the sausages, but you could add another splash if necessary. Stir in the dried thyme.

Step 9: Stir the onions and mushrooms over moderate heat until the onions become translucent and the mushrooms release their moisture.

Step 10: Stir the gravy granules into 2 cups of boiling water in a measuring jug, then pour it into the onions and mushrooms. Taste the gravy for seasoning and add salt if necessary.

Assemble and bake

Step 11: Pour the gravy over the sausage balls in the casserole dish.

Step 12: Spoon the mash carefully over the sausages and gravy, and use a fork to spread it evenly. Sprinkle with grated cheese.

Step 13: Place the dish in a preheated oven at 180 °C (fan) or 200 °C (conventional) / 365 °F (fan) or 400 °F (conventional) and bake for half an hour or until the cheese is melted and golden.

Tips for a successful outcome

Here are my top tips to ensure your sausage and onion bake always turns out perfectly:

• Cook the leeks and cabbage over moderate heat to avoid burning. They should not take on any colour, and should soften to the point where you are able to mash them with the potatoes.
• I like to remove the sausage meat from the casings and form it into balls - I find it browns more easily. You could simply brown the whole sausages and then cut them into pieces before placing them in the casserole dish.
• Don't worry about cooking the sausage balls completely. They will continue to cook once the dish goes into the oven.
• The same goes for the mushrooms and onions - you should soften them, but still leave a bit of a bite.
• Season the dish to taste before adding the potato topping. Different brands of gravy granules have different levels of seasoning. Taste first and adjust if necessary.
• When covering the dish with the mash, carefully place spoonfuls of mash on top of the gravy, then use a fork to spread it.
• Place the casserole dish on a baking sheet before putting it into the oven to protect the bottom of your oven from any gravy that might bubble up and overflow.

Variations

There are always things you can do to modify a recipe to suit your own taste. Here are a few ideas you might like to try:

• Mustard. Add a teaspoon of Dijon mustard to the gravy, and stir a tablespoon of wholegrain mustard through the mash.

• Curry. Add a tablespoon of your favourite curry powder to the gravy.
• Deluxe. Swap half a cup of water for half a cup of red wine for a richer taste.
• Veggies. Instead of serving a green vegetable on the side, add a cup of peas, green beans or broccoli florets to the filling before it goes into the oven.

Equipment

These are the main items of equipment you will need for this sausage casserole:

• Saucepans - for boiling the potatoes and softening the leeks and cabbage.
• Frying pan - which will be used to fry the sausage balls and make the onion and mushroom gravy.
• Casserole dish - which should be large enough to hold the sausages and gravy with the potato-vegetable mash on top.
• Baking tray - to catch any gravy that might overflow from the casserole dish while it is in the oven.

Storing and freezing

• Refrigerator. Transfer leftovers to a suitable lidded container (or leave them in the covered casserole dish) and store them in the refrigerator for up to 2 days.
• Freezer. Allow to cool completely, then transfer any leftovers to a rigid freezer container (such as Tupperware) and freeze for up to 3 months.
• Defrosting. Defrost in the refrigerator before reheating. If you are in a hurry, use the defrost setting on your microwave.
• Reheating. If you've stored leftovers in the casserole dish, reheat it in the oven at 160C or 325F for 10 to 15 minutes until piping hot. Otherwise, transfer the leftovers to a saucepan and reheat them gently over moderate heat on the stove.
• Make-ahead meal prep. You could also assemble the dish in disposable aluminium containers and freeze (without baking) for up to 3 months. Bake from frozen, but add an extra 5 to 10 minutes to the cooking time to compensate.

Save for later

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