Spaghetti Squash Gratin with Walnut and Bacon Recipe

Gratin de courge spaghetti, noix et lardons

It saddens me when people attemp to pass off food items as something they’re not: they’re selling those foods short, and setting eaters up for disappointment. No, meatless burgers are not at all like beef burgers, carob chips have nothing to do with chocolate chips, and I don’t know in what parallel low-carb universe spaghetti squash is seen as an acceptable substitute for actual, durum wheat spaghetti.

But those food items do have unique qualities of their own — well, except for carob, which is vile — so why not simply tout them as such?

Going back to the spaghetti squash, it deserves a lot better than to be treated as a stand-in for pasta. It is a wonderful winter squash in its own right, with a delicate flavor that’s not too sweet, and it is therefore a good choice for those who find winter squash a bit cloying.

But its most distinguishing feature — and the source of the misunderstanding — is its flesh, which easily separates into soft strands when cooked. The spaghetti comparison ends there, naturally, but those little tufts of filaments do create a delightfully fluffy mouthfeel that sets this cucurbitaceae apart from its peers.

Some recipes suggest cooking spaghetti squash in the microwave, but I no longer own one, so I just roast it in the oven — a method that is all in all preferable, as it also serves to deepen the flavor of the squash and evaporate some of its moisture, preventing it from getting soggy. All you need to do then is run a fork across the flesh, and the strands will appear before your very eyes, like magic.

In late afternoon on Sunday, as I was pondering what to do with my gourd, I got many great suggestions through a Twitter brainstorm: Kim likes to cook the strands like potato pancakes, with green onions, ginger and soy sauce; Anna eats her spaghetti squash with tomato soup; Yasmin dresses hers with pesto and chili oil; Michelle pointed me to this Gourmet recipe; Ariane suggested brown butter and sage; Lucy likes to layer the squash lasagna-like, alternating with spinach and ricotta and a Moroccan-inspired tomato-lentil sauce.

But, as is usually the case in my kitchen, I ended up devising a recipe inspired by what I had on hand: the thickish slice of smoked bacon that needed using, the bowl of walnuts from our neighbor’s sister’s garden, and the butt end of a mozzarella log I’d bought for a pizza aux cèpes made with ceps I hunted and captured in the forest last Thursday (see below).

This lineup of ingredients spelled gratin quite clearly: I roasted the spaghetti squash, arranged half of the flesh in a baking dish, sprinkled it with browned strips of the bacon and crumbled walnuts, layered the rest of the squash on top, covered with thinly sliced mozzarella, and topped with breadcrumbs to foster crunch. The whole thing went back under the oven grill for a few minutes, and then dinner was ready.

We had it as our main course, which left room for slivers of salted butter caramel tatin left over from the previous day’s dinner party, but it would also be lovely as a side and, come to think of it, a most suitable one if you’re cooking for Thanksgiving this week.

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Spaghetti Squash Gratin with Walnut and Bacon Recipe

Prep Time: 30 minutes

Cook Time: 45 minutes

Total Time: 1 hour, 15 minutes

Serves 4 to 6.

Spaghetti Squash Gratin with Walnut and Bacon Recipe


  • 1 spaghetti squash, about 2 kilos (about 4 1/2 pounds)
  • 1 thick slice of smoked bacon, about 30 grams (1 ounce) (in France, ask for poitrine fumée)
  • 12 walnut halves, roughly crumbled
  • 60 grams (2 ounces) "dry" mozzarella (i.e. not sold in whey, i.e. the kind you would use for pizza or lasagna), sliced thinly
  • 2 to 3 tablespoons dried breadcrumbs (unseasoned; I make mine by just grinding stale leftover baguette; use gluten-free breadcrumbs as required)
  • olive oil
  • ground chili pepper (optional; I use piment d'Espelette)
  • salt, pepper


  1. Preheat the oven to 190°C (375°F) and lightly grease a baking sheet.
  2. Using caution and a sharp chef's knife, cut off a slice on both ends of the spaghetti squash, to remove the stem and the bottom. Set it upright on the cutting board, and slice it vertically in two equal halves. Scrape, scoop out, and discard the seeds and stringy flesh. Rub the insides of each half with olive oil, then sprinkle with salt, pepper, and ground chili pepper.
  3. Place both halves on the prepared baking sheet, cut side up, and place in the oven to roast for 40 minutes, until lightly browned and fragrant. A knife should meet minimal resistance when you try to pierce the flesh, but the squash should not feel completely soft, or it may be overcooked and therefore bland. Set the squash halves aside to cool for a few minutes, until you can bear to handle it. Turn off the oven.
  4. While the squash is roasting, slice the bacon into thin strips (lardons), about 5 mm wide (1/5 inch). Place them in a small skillet and cook over medium heat until they've released most of their fat and they're nicely browned. Scoop them out of the skillet and set them on a plate lined with a (single) paper towel.
  5. Lightly grease a medium baking dish, about 2 liters (2 quarts) in capacity.
  6. When the squash is just cool enough to handle, run a fork across the flesh to separate it into strands. Scoop out and arrange the flesh from one half of the squash to form a layer at the bottom of the pan. Season with salt and pepper, then sprinkle evenly with the bacon strips and walnuts. Arrange the remaining squash flesh in second layer, season with salt and pepper, and top with the thinly sliced mozzarella to just about cover the surface. Sprinkle with the breadcrumbs.
  7. (You can prepare the gratin ahead up to this point. Let cool completely, cover, and refrigerate until ready to reheat and serve.)
  8. Switch the oven on again to 190°C (375°F); no need to preheat it again, as it should still be quite warm. Return the dish to the oven for 5 minutes, until the squash is heated through again (if you've refrigerated the gratin, you'll need to preheat the oven and it will take a little longer to reheat -- say, 15 minutes) then switch to grill mode for a few minutes, until the cheese topping is melted and browned. Serve immediately.

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