Cheesy Creamy Winter Butternut Squash Gratin

Name: Cheesy Creamy Winter Butternut Squash Gratin
Prep time: 20 min
Cook time: 40 min
Total time: 60 min
Ingredients: 1 small knob of butter; 1 tbsp olive oil; 2 red onions (halved and thinly sliced); 2 garlic cloves (crushed); 8 sage leaves (finely chopped); 28 oz butter beans (drained; about 4 1/2 cups); 10 fl oz heavy cream (double cream) (about generous 1 1/4 cups); 6.75 fl oz milk (about scant 1 cup); 2 tbsp wholegrain mustard; 1 butternut squash (peeled, seeds removed, quartered, and thinly sliced (about 2lb 2oz/950 g prepared weight)); 3.5 oz grated Gruyère (about generous 3/4 cup); 1.75 oz grated cheddar (about scant 1/2 cup)

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This Cheesy Creamy Butternut Squash and Butter Bean Gratin is so incredibly good! It’s a luxurious and comforting vegetarian main course or side dish that celebrates the sweetness of butternut squash with a gorgeous cheesy element, lots of aromatic sage, and wonderfully plump and creamy butter beans. It’s a soul-warming addition to any autumn or even Christmas table.

Close up of a piece of squash gratin on a white plate with a fork.

Why you will love this recipe
Ingredients
Substitutions and variations
How to make cheesy creamy winter butternut squash gratin
Tips from Margie’s kitchen
Frequently asked questions
Other recipes you may enjoy
Cheesy Creamy Winter Butternut Squash Gratin Recipe
Make-ahead and storage

In French, ‘au gratin’ means it has been sprinkled with cheese or breadcrumbs and browned on top. The browning on the top is the key part. Since this recipe involves covering the top in cheese before baking until golden brown, it is a true gratin recipe (they’re not just made from potatoes!) perfect to be served with a simple vegetable side (frozen peas are great if you’re looking for something to cook quickly) or even a dressed salad. The addition of butter beans really is what takes this butternut squash gratin from being a side dish and turns it into a proper meal.

And, if you have another type of squash on hand such as a Crown Prince squash or even a pumpkin, this could be renamed a Winter Squash Gratin – you don’t have to just stick to butternut!

Why you will love this recipe

It’s a warming, comforting dish that celebrates butternut squash while it’s in season.
The butter beans turn it from a side dish into a satisfying vegetarian main.
Simple to make with everyday ingredients, and you can easily swap in any winter squash.
The cheesy golden top makes it feel indulgent, even though it comes together with minimal fuss.

Ingredients

This Butternut Squash Gratin is made from simple, easy-to-find ingredients, but there are a few choices you can make to guarantee it comes out perfectly every time!

Butter – In this recipe, it does not matter if you use salted or unsalted.
Red onions – Thinly sliced red onions add a nice flavor to the gratin.
Garlic cloves – Crush the garlic or grate it on a microplane.
Sage leaves – You want finely chopped sage. Rosemary or fresh thyme leaves would work well, too.
Butter beans – You can use canned beans, but jarred gives a much better texture. We like Bold Bean Co.
Heavy cream (double cream) – We’ve used 300 ml ( 10 fl oz) here as it’s a common package size in the UK. If your cream comes in slightly different measures, don’t worry about adding slightly more or slightly less cream to use it all up.
Milk – Whole milk or semi-skimmed are both fine, but skimmed milk will detract from the creaminess you want.
Wholegrain mustard
Butternut squash – Peel and deseed the squash, quarter it, then slice thinly. Other winter squash are great alternatives.
Grated Gruyère and cheddar – If you only have one cheese, you’ll still get a delicious gratin, but it is better made with both! Also, if you’re cooking for vegetarians, make sure your choice of cheese reflects this.

Substitutions and variations

Squash: If you don’t have butternut squash, try a different winter squash, like Crown Prince or even pumpkin. Simply swap in the same prepared weight.

Butter beans: Canned butter beans work well and are the easiest option. If you can find good-quality jarred beans, use them, as they tend to have a creamier texture.

Herbs: While sage is a classic in a butternut squash gratin, chopped rosemary or fresh thyme work well as a swap.

How to make cheesy creamy winter butternut squash gratin

ONE: Heat the butter and oil in a large frying pan over low-medium heat. Slowly sauté the onions, stirring occasionally, for about 10 minutes, until soft. Add the garlic and sage, and cook for another minute until fragrant.

TWO: Add the butter beans, mustard, milk, and cream, seasoning with salt and pepper. Stir well.

THREE: Preheat the oven to 392°F (200°C/180°C fan). In a large ovenproof dish, layer 1/3 of the squash, followed by 1/2 of the butter bean mix, and a handful of grated cheese.

FOUR: Repeat with a second layer of squash, butter beans, and cheese. Finish with a layer of squash, then the remaining cheese.

FIVE: Bake for about 40 minutes, until the cheese is melted and golden and the squash is tender. Let the gratin rest for 5 minutes before serving.

Butternut squash gratin in dish with serving spoon.

Tips from Margie’s kitchen

Slice evenly: Try to slice the squash into thin, even pieces. This helps it cook through at the same rate as the gratin’s other layers, so you don’t end up with undercooked bits.
Get a golden top: If the top isn’t as golden as you’d like, pop it under the broiler for the last couple of minutes to finish it off. Just keep a close eye so it doesn’t catch.
Make it ahead: You can assemble the butternut squash gratin up to a day in advance. Keep it covered and in the fridge unbaked. Add a few extra minutes to the cooking time if baking straight from cold.

Frequently asked questions

Is it necessary to peel butternut squash before cooking?

In this recipe, we think it is best to peel the squash because you want the whole dish to melt together and be really smooth and soft.

What is the best way to cut the rind off of the butternut squash?

Having a sharp peeler really takes the work out of it. This one from OXO is great, or this one too. If you are really stuck, slice off the top and bottom of the squash, prick it all over with a fork, and place it in the microwave on high for 3 minutes. This just starts to cook the outside of it, which softens it enough to help a peeler glide through!

Why do I have to rest the butternut squash gratin before serving?

Resting the gratin for at least 5 minutes before serving helps it settle a little, and makes sure the layers don’t collapse as you dish up individual portions. This is a good habit to get into when making any kind of gratin, as well as when making something like a simple lasagne (with a cheat’s white sauce).