Tromboncino Gratin – Easy Cheesy Comfort Food Bake
Creamy tromboncino gratin recipe with cheese and cream. A comforting bake that works as a vegetarian main or rich, cheesy side dish.
If you’ve grown tromboncino this year, chances are you’ve got plenty to use up — and this creamy tromboncino gratin is one of the most comforting ways to showcase this versatile squash.
Baked until bubbling and golden, it’s equally delicious served as a hearty vegetarian main with a fresh salad or as a rich, cheesy side to your favourite roast.
About Tromboncino Squash
Tromboncino, sometimes called zucchetta, is a long, pale-green Italian heirloom squash with a sweet, delicate flavour. Unlike courgette (zucchini), it stays firm when cooked and has a slightly sweet and nutty flavour.
In my opinion, it is the most underappreciated vegetable out there, and it beats courgette in every way. I don’t understand why so many people grow endless amounts of courgette and ignore some of the far superior squash varieties.
Tromobonico squash are incredibly versatile. Because they don’t fall apart when cooking they can be stuffed and roasted while keeping their shape, and because they are not packed full of water, they can be added to curries without turning to mush. Their similarity to courgette means you can spiralise them to make “Zoodles” (or should we say Toodles?). They can even be grated like courgette and added to sweet baking products.
Yes, everything a courgette can do, tromboncino can do it better.
Key Ingredients Breakdown
Tromboncino squash
The mild nutty flavour and firm texture hold up perfectly when baking in a cream sauce, and the sugars in the squash help it caramelize nicely. For a recipe like this, there is no need to remove the skin.
The neck of the squash should be cut into discs around half a centimetre thick. When you get to the bulbous end you will find the seeds. It’s up to you if you remove them or not. They are like courgette seeds, and completely edible. I chose to remove them because I know my four year old would not touch the food if she saw them. It’s entirely up to you.
If you want to try this recipe, but cant find tromboncino squash, I would recommend against trying it with courgette. They contain too much water and it will just be like a creamy soup with mushy vegetables inside. I would opt instead for a Butternut Squash.
Double Cream
The base of the sauce that the tromboncino will cook in. This recipe doesn’t skimp on the cream. If you were looking to reduce the calories, you could swap half the cream out for whole milk, but I wouldn’t swap out more than half, otherwise it will end up too watery. A thin bechamel would allow you to reduce the calories even further but without losing the thick sauce.
Cheese
We will be mixing two cheeses for this dish.
Firstly, a relatively strong flavoured hard cheese like Cheddar or Gruyère. Half of it will go into the cream sauce, and the other half will be sprinkled on top for a crispy cheesy topping.
Secondly, a Grana type cheese. so either Parmesan or Grana Padano. This will be sprinkled on the top and make the cheesy topping mega crispy.
Step-by-Step Instructions
1. Preheat the oven
Begin by preheating your oven to 190°C (375°F). Lightly grease a medium baking dish, about 28 × 20 cm with a 2-litre capacity. This will help stop it from sticking and encourages those golden, crispy edges everyone loves in a gratin.
2. Prepare the tromboncino
Slice the squash into thin rounds, roughly half a centimetre thick. If your tromboncino is very large, cut it in half lengthwise before slicing so the pieces layer neatly. A mandoline slicer is handy here for quick, even cuts, but a sharp knife works perfectly well.
You can leave the skin on for this recipe. The seeds can be left in or taken out as you see fit.
3. Cook the aromatics
In a large frying pan, melt butter together with olive oil over medium heat. Add the onion and garlic, cooking slowly for five to seven minutes. Stir often and take care not to let them catch or brown too much.
4. Make the creamy sauce
Stir in the cream along with half of the grated hard cheddar (or alternative), then season with herbs, a little salt, and freshly ground black pepper. Keep the heat low so the sauce warms gently and the cheese melts smoothly into the cream.
5. Assemble the gratin
Spread a layer of tromboncino slices across the bottom of your prepared dish, then spoon a small amount of the sauce over the slices. It doesn’t need a lot. We just want a small coverage for where the next squash slice will sit.
Continue to layer the slices and topping with a small amount of sauce until all the squash is used up. Then pour the remaining sauce over the squash and press lightly all over, ensuring that all tromboncino has been doused in the cheese cream sauce.
6. Add the topping
Scatter the remaining Cheddar and then the Parmesan over the top, and, if you enjoy a bit of crunch, sprinkle with breadcrumbs as well.
7. Bake until bubbling
Place the dish on the middle shelf and bake for 30 to 35 minutes. The gratin is ready when the top is bubbling and golden brown, and the tromboncino is tender enough to pierce easily with a knife.
8. Rest and serve
Remove from the oven and let the gratin rest for five to ten minutes before serving. This short pause helps the layers settle, making it easier to cut and serve neat portions, and will cool it down from “roof of mouth blistering napalm hot”, to just regular oven hot.
Enjoy it as a warming vegetarian main with a fresh salad, or bring it to the table as a rich, cheesy side dish to accompany your favourite roast.
Tromboncino Gratin – Easy Cheesy Comfort Food Bake
Ingredients
- 1 kg tromboncino
- 1 large onion thinly sliced
- 3 cloves garlic crushed
- 350 ml double cream
- 125 g Cheddar grated
- 65 g Parmesan finely grated
- 35 g butter
- 1 tbsp olive oil
- 1 tsp dried thyme or oregano optional
- 3 tbsp breadcrumbs optional, for topping
- salt and black pepper
Instructions
- Preheat the oven to 190°C (375°F) and lightly grease a 28 × 20 cm (or similar size) baking dish.
- Slice the tromboncino into thin rounds, about 5 mm thick. If very large, halve lengthwise first for neat layers.
- Melt butter with olive oil over medium heat. Add onion and garlic and cook for 5–7 minutes until soft but not browned.
- Reduce the heat and stir in the cream, along with half the grated cheese, herbs, salt, and pepper. Warm gently until smooth — don’t let it boil.
- Arrange a layer of tromboncino slices in the dish, spoon a little sauce over the tromboncino slices, and repeat, finishing by pouring all the sauce over the top.
- Sprinkle with the remaining grated cheese, the Parmesan, and the breadcrumbs if using.
- Bake for 30–35 minutes until bubbling, golden, and the squash is tender when pierced.
- Rest for 5–10 minutes before serving so the layers hold together when sliced.
