Here’s a detailed Slow Cooker Cheesy Potato & Caramelised Onion Bake recipe—rich, creamy, and perfect as a side or even a main dish.
🧀 Slow Cooker Cheesy Potato & Caramelised Onion Bake
🛒 Ingredients (Serves 4–6)
Base
- 1 kg potatoes (Yukon Gold or Maris Piper work best), thinly sliced
- 2 large onion, thinly sliced
- 2 tbsp butter
- 1 tbsp olive oil
- 2–3 cloves garlic, minced (optional but recommended)
Cheese sauce
- 2 tbsp butter
- 2 tbsp plain flour
- 2 cups milk (whole milk gives best texture)
- 1½–2 cups grated cheddar cheese
- ½ tsp salt
- ½ tsp black pepper
- ½ tsp mustard powder (optional, boosts flavour)
Extras (optional but delicious)
- ½ tsp thyme or rosemary
- Pinch of nutmeg
- Extra cheese for topping
- Chopped spring onions for garnish
🧅 Step 1: Caramelise the onions (key flavour step)
- Heat butter + olive oil in a pan over low–medium heat.
- Add sliced onions and a pinch of salt.
- Cook slowly for 25–35 minutes, stirring occasionally.
- Onions should turn golden brown, soft, and sweet.
- Add garlic in the last 2–3 minutes. Set aside.
This step builds the deep, sweet flavour—don’t rush it.
🥔 Step 2: Make the cheese sauce
- Melt butter in a saucepan over medium heat.
- Stir in flour and cook for 1–2 minutes (this makes a roux).
- Slowly whisk in milk to avoid lumps.
- Cook until thickened (about 4–6 minutes).
- Remove from heat and stir in:
- Cheddar cheese
- Salt, pepper, mustard powder
- Mix until smooth and creamy.
🧄 Step 3: Assemble in slow cooker
- Lightly grease the slow cooker pot.
- Add a layer of sliced potatoes.
- Add a layer of caramelised onions.
- Pour some cheese sauce over.
- Repeat layers until everything is used.
- Finish with extra cheese on top.
Optional: Add thyme between layers for aroma.
⏲️ Step 4: Slow cook
- Low setting: 5–6 hours
- High setting: 3–4 hours
Check doneness:
- Potatoes should be tender when pierced with a fork.
- Top should be golden and bubbling at edges.
🧀 Step 5: Finish & serve
- Let it rest for 10–15 minutes before serving (it sets nicely).
- Sprinkle spring onions or extra cheese if desired.
- Serve with salad, roast chicken, or as a comfort main dish.
💡 Tips for best results
- Slice potatoes evenly so they cook uniformly.
- Don’t skip caramelising onions—it’s the “wow” flavour layer.
- If it feels too thick, add a splash of milk before slow cooking.
- For extra richness, mix in a bit of cream with the milk.
If you want, I can also:
- turn this into an oven-baked version with crispy top
- make it healthier / low-calorie
- or adapt it for chicken or vegetarian main dish variations