Butternut Squash and Blue Cheese Bake - Easy Sunday Side Dish

A gorgeous, golden butternut squash bake with caramelised onions, sage, a creamy blended squash sauce, and crumbled blue cheese on top. It sounds fancy, it looks incredibly impressive on the table. This is your new favourite Sunday side dish. Butternut squash is one of those vegetables that is SO cheap when it is in season, we are talking four dollars for a squash bigger than my head, and this recipe makes the absolute most of every single bit of it. Welcome to another episode of The Weekly Veg!

Watch me make this on YouTube!

Recipe Details:

• Prep Time: 20 minutes
• Cook Time: 1 hour (including roasting and baking)
• Total Time: 1 hour 20 minutes
• Serves: 6 as a side dish
• Difficulty: Easy
• Special Equipment: Air fryer or oven, blender or stick blender, small baking dish

The genius of this recipe is that the butternut squash does two completely different jobs. The bottom half gets diced and roasted until soft and golden, then half of it goes into the blender with chicken stock and milk to make the most incredible creamy sauce, and the other half gets layered into the bake. The top half of the squash is thinly sliced and layered over the top, and as it bakes it becomes tender and golden and absolutely beautiful. One vegetable, two textures, one seriously impressive dish. The blue cheese on top is the finishing touch that takes the whole thing from delicious to EXTRAORDINARY.

Why You'll Love This Recipe

• Incredible value: Butternut squash is one of the cheapest vegetables you can buy when it is in season and this recipe uses the whole thing
• Looks stunning on the table: Golden layered squash on top with bubbling blue cheese, this is a proper showstopper side
• Clever use of the whole vegetable: Diced for the base, blended for the sauce, and sliced for the top, nothing goes to waste
• Make ahead friendly: Assemble ahead of time and just pop it in the oven when you need it
• Pairs with everything: A brilliant side for a Sunday roast, a dinner party, or anything that needs a little something special alongside

Ingredients

For the Roasted Squash:

• 1kg butternut squash, divided (bottom half diced, top half thinly sliced)
• 2 cloves garlic, left whole for roasting
• Olive oil, for roasting
• Salt and pepper, to season

For the Caramelised Onions:

• 2 onions, thinly sliced
• 2 cloves garlic, finely chopped
• 5 large fresh sage leaves, finely sliced
• Olive oil or butter, for cooking

For the Sauce:

• 600ml chicken stock
• 200ml milk
• Half the roasted diced squash (from above)
• Salt and pepper, to season

To Assemble:

• Remaining roasted diced squash
• Caramelised onions
• Thinly sliced raw squash (top half)
• 80-100g mild creamy blue cheese, crumbled

Instructions

1. Prep the squash: Preheat your oven to 180°C (160°C fan / 350°F / Gas Mark 4). Cut the butternut squash in half. Dice the bottom half into roughly 2cm chunks and set the top half aside for slicing later. Thinly slice the top half of the squash as finely as you can,  the thinner the better as this is what goes on top of the bake and you want it to cook through evenly and turn golden. A mandoline makes this easy if you have one! (obviously use as much as you need you can see in the video I only sliced half of the top and I still have to much)
2. Roast the diced squash: Toss the diced squash and 2 whole garlic cloves in olive oil, season well with salt and pepper, and roast in the air fryer at 200°C for 15 to 20 minutes until soft and golden. Alternatively roast on a tray in the oven at 200°C for 25 minutes. You want it tender all the way through with a little colour on the edges.
3. Caramelise the onions: While the squash is roasting, heat a pan over medium-low heat with a drizzle of olive oil or a knob of butter. Add the sliced onions and cook slowly for 15 to 20 minutes, stirring occasionally, until they are deeply golden, soft, and sweet. Add the chopped garlic and sliced sage for the last 3 to 4 minutes and stir through. Take your time with this step, properly caramelised onions. I also like to add in a 1/2 tsp of salt to help soften and then carmalise. 
4. Make the sauce: Once the diced squash is roasted, add half of it to a jug or blender along with the chicken stock and milk. Blend until completely smooth. Taste and season well with salt and pepper. The sauce should be creamy, golden, and absolutely gorgeous.
5. Assemble the bake: In a small baking dish, combine the remaining roasted diced squash and the caramelised onions. Pour the blended sauce over the top and give everything a gentle stir to combine. Lay the thinly sliced raw squash over the top in an even layer, overlapping slightly as you go. Crumble the blue cheese generously over the top.
6. Bake: Cover the dish with foil and bake at 180°C (160°C fan / 350°F / Gas Mark 4) for 30 minutes. Remove the foil and bake for a further 10 minutes until the top is golden and the sliced squash is cooked through and tender. If your squash slices are on the thicker side it may need an extra 5 to 15 minutes, just keep an eye on it. A knife should slide through the top layer with no resistance when it is done.
7. Serve: Leave to rest for 5 minutes before serving. It is absolutely gorgeous straight from the dish, golden and bubbling and smelling incredible!

Chef's Tips

Slice the top half as thinly as you can: This is the most important tip for this recipe. Thin slices cook through evenly and turn beautifully golden on top. Thick slices can stay underdone in the middle. Use a mandoline if you have one or take your time with a sharp knife.

Freeze your onions pre-sliced: If you want to save time, slice a big batch of onions and keep them in a bag in the freezer. They go straight into the pan from frozen and caramelise just as beautifully. A brilliant little time saver!

Don't rush the caramelised onions: Low and slow is the only way to properly caramelise onions. Turning the heat up to speed things along gives you soft onions, not caramelised ones. The sweetness and depth they add to this dish is worth every minute.

Use a mild creamy blue: A strong blue cheese can overpower the delicate sweetness of the squash. Go for something mild and creamy like Kāpiti Kikorangi or a similar mild blue. You still get that gorgeous salty, tangy punch without it taking over.

Make ahead: You can assemble the whole bake up to the point of going in the oven, cover it, and keep it in the fridge for up to a day. Just add an extra 5 to 10 minutes to the covered baking time if going in cold from the fridge.

Substitutions & Variations

• Blue cheese: Swap for feta for a milder, saltier finish, or goat's cheese for something creamy and tangy
• Chicken stock: Vegetable stock works just as well and makes this a vegetarian dish
• Sage: Fresh thyme or rosemary are both beautiful here instead
• Milk: Any milk works including oat milk or almond milk for a dairy-free option alongside dairy-free cheese
• Butternut squash: Pumpkin works beautifully as a swap when butternut is out of season

Storage

Fridge: Cover and store in the fridge for up to 3 days. Reheat covered with foil at 160°C for 15 to 20 minutes until heated through.

Freezer: This bake freezes well for up to 2 months. Cool completely, cover tightly, and freeze. Defrost overnight in the fridge before reheating.

Leftovers: Leftover bake is incredible the next day warmed up and served alongside some crusty bread for lunch!

Frequently Asked Questions

Q: Can I use frozen butternut squash? A: Fresh is definitely best here, especially for the sliced top layer. Frozen diced squash can work for the base and the sauce but won't slice for the top layer, so stick to fresh for that part.

Q: My top layer isn't cooked through, what do I do? A: Cover it back up with foil and give it another 10 minutes. This almost always comes down to slice thickness. Thinner next time and you won't have this problem!

Q: Can I make this as a main rather than a side? A: Absolutely! Serve it with some crusty bread and a simple green salad and it is a completely satisfying vegetarian main for 3 to 4 people.

Q: I don't have an air fryer, can I roast the squash in the oven? A: Yes! Roast on a lined baking tray at 200°C (180°C fan / 400°F / Gas Mark 6) for 25 minutes, tossing halfway through, until golden and tender.

Q: Can I use pumpkin instead of butternut squash? A: Yes, any firm-fleshed pumpkin works beautifully here. Just make sure whatever you use is firm enough to slice thinly for the top layer.

You Might Also Like

Brussels Sprout Caesar Salad with Crispy Rice - Easy Recipe - Another brilliant seasonal vegetable recipe that will completely change the way you think about Brussels sprouts!

Kale and Potato Bake - Easy Seasonal Vegetable Recipe - A gorgeous, comforting bake that would sit beautifully alongside this butternut squash one on a Sunday table!

5 Minute Asian Green Beans - Quick Side Dish - The quickest, most flavourful side dish you will ever make. A Weekly Veg favourite!

Enjoy!

Del x

This butternut squash and blue cheese bake is the Sunday side dish that will have everyone asking for the recipe. Roasted squash two ways, deeply caramelised onions, a creamy blended squash sauce, and crumbled blue cheese on top, all baked together into something truly SPECIAL. Seasonal, budget friendly, and absolutely delicious.