📌 Zucchini-Tomato Gratin
Posted 30 April 2026 by: Admin
That smell of gratinating cheese, slightly charred around the edges, filling the entire kitchen ten minutes before the dish comes out. That is what zucchini-tomato gratin is all about. No technique, no endless grocery list — just everyday vegetables and an oven that does almost all the work.
The surface is golden like a light caramel, dark in some spots around the edges of the dish where the cheese melted against the hot ceramic. Underneath, the zucchinis have gently released their water, becoming soft and translucent, and the tomatoes have candied, letting their juices mingle with the creamy mixture. One scoop in, and it barely resists before giving way. The smell is of Herbes de Provence and warm milk, with that slightly tangy tomato base that has had time to concentrate.
Why you’ll love this recipe
Ingredient Notes
Everything you need for this gratin: simple summer vegetables, eggs, cream, and shredded cheese.
- Zucchini : Choose firm ones, not too large — a 25 cm zucchini with thick seeds is often bitter and watery. Small ones, around 200 g each, have denser flesh and less water. No need to peel them.
- Tomatoes : Here, ripeness truly changes the result. A slightly soft, deep red tomato that smells good when you cut it — that’s the one you want. Firm, overly shiny supermarket tomatoes in winter will release watery, acidic juice. In summer, garden or market tomatoes make it a whole different recipe.
- Heavy cream and eggs : This is the ‘appareil’, the binder that holds everything together. Two eggs and 20 cl of heavy cream — not light cream, which won’t set as well and will yield a less creamy result. Whisk them with salt, pepper, and perhaps some herbs, and it’s ready.
- Shredded cheese : Emmental or Gruyère are the best for melting and gratinating. Shredded mozzarella gives a stretchier, milder result, great for kids. Comté brings more character. Avoid industrial ‘4-cheese’ blends — they often contain starch and brown strangely.
Pre-cook the zucchini — it’s the one thing that changes everything
The classic problem with zucchini gratin is water. Zucchinis contain a huge amount of it, and if you place them raw in your dish, they will release it all during cooking. Result: a liquid bottom, a diluted creamy mixture, and vegetables vaguely floating in juice. Five to seven minutes in a pan with a drizzle of olive oil over medium heat — you hear 그 small whistling sound as the water evaporates; that’s exactly what you want. The zucchinis become slightly translucent at the edges and start to smell good. If they are still a bit firm, that’s fine; they will finish cooking in the oven. The onion and garlic go in the same pan, flavoring gently without dominating.
Assemble the dish without overthinking it
A layer of zucchini, a layer of tomatoes, then repeat. That’s it. No need to layer in a precise order or alternate millimeter by millimeter — what matters is that the vegetables fill the dish well without leaving large gaps, and that the tomatoes are distributed rather than concentrated in one spot, because they will release juice. Pour the cream-egg mixture over the top to cover everything. You’ll see the amber liquid seep between the layers of vegetables. A generous handful of shredded cheese on top, and you’re good to go.
Don’t touch anything for 35 minutes
180°C, preheated oven, 35 minutes. Resist the urge to open the oven every ten minutes to check. The gratin needs time for the mixture to truly set, for the vegetables to melt, and for the cheese to form that golden crust on the surface. Toward the end, if the top still looks pale, give it two or three minutes under the broiler. The target color is a uniform golden-brown with a few darker spots — not a shy blonde, nor black. Remove from the oven. Wait five minutes before serving: this rest period allows it to hold together when you plunge the spatula in.
Tips & Tricks
- Don’t oversalt the cream-egg mixture: the shredded cheese already provides salt, and the zucchinis were salted in the pan. Better to taste before adding more.
- If your tomatoes are very watery, seed them before slicing — remove the seeds with a small spoon to reduce moisture in the dish without sacrificing flavor.
- The next day cold, this gratin is almost better: the mixture has set perfectly, the flavors have melded, and the zucchinis have absorbed any remaining tomato juice.
How do I prevent the gratin from being too watery?
The main cause is raw zucchinis placed directly in the dish. By sautéing them for 5 to 7 minutes in a pan before assembly, they release their water before baking. If your tomatoes are very juicy, seed them with a small spoon before slicing.
Can this gratin be prepared in advance?
Yes, it’s actually quite convenient. Assemble the complete gratin (vegetables + mixture + cheese) the day before, cover the dish with plastic wrap, and keep it in the refrigerator. The next day, take it out 15 minutes before baking and add 5 extra minutes of cooking time to account for the cold.
Does zucchini-tomato gratin freeze well?
Honestly, not ideally. Zucchinis and tomatoes release a lot of water when thawing, which softens the texture and makes the mixture soggy. It’s better to keep it for 3 days in the refrigerator and reheat at 150°C covered with foil.
Can I replace the heavy cream?
Whole milk works but gives a less creamy result and the mixture won’t hold together as well when sliced. Crème fraîche diluted with a little milk is a good alternative. Avoid light plant-based creams as they tend to split during cooking.
Which cheese should I use for a good gratin?
Emmental and Gruyère are reliable choices — they melt uniformly and form a beautiful golden crust. Comté adds more flavor. Shredded mozzarella gives a milder, stretchier result. Avoid industrial blends which often contain starch and brown unevenly.
Can this gratin be served as a main course?
Absolutely. Accompanied by a well-dressed green salad and a piece of bread, it makes a complete and satisfying meal. To make it even more substantial, add some turkey bacon bits between the vegetable layers during assembly.
Zucchini-Tomato Gratin
French
Main course
A melting, golden gratin with a cheesy crust, featuring zucchinis and tomatoes candied in a creamy egg-cream mixture. Simple, family-friendly, and effective.
Ingredients
- 2 (about 400g) zucchinis
- 3 (about 450g) tomatoes
- 100g shredded cheese (Emmental or Gruyère)
- 20cl heavy cream
- 2 eggs
- 1 onion (optional)
- 1 garlic clove (optional)
- 1 tablespoon olive oil
- 1 teaspoon Herbes de Provence (or chopped basil)
- to taste salt and pepper
Instructions
- 1Preheat the oven to 180°C. Lightly grease a gratin dish.
- 2Wash the zucchinis and tomatoes. Slice the zucchinis into 5 mm rounds. Slice the tomatoes into rounds. Mince the onion and chop the garlic if using.
- 3Heat the olive oil in a pan over medium heat. Sauté the zucchinis with the onion and garlic for 5 to 7 minutes until they begin to soften. Salt lightly. Set aside.
- 4In a mixing bowl, whisk the 2 eggs with the heavy cream, salt, pepper, and Herbes de Provence until smooth.
- 5Arrange a layer of zucchinis in the dish, followed by a layer of tomatoes. Repeat until all vegetables are used.
- 6Pour the cream-egg mixture evenly over the vegetables. Spread the shredded cheese over the entire surface.
- 7Bake for 35 minutes until the top is well browned. To enhance the gratin finish, place under the broiler for 2 to 3 minutes at the end of cooking.
- 8Let rest for 5 minutes out of the oven before serving.
Notes
• Storage: keeps for 3 days in the refrigerator. Reheat at 150°C covered with aluminum foil for 15 minutes.
• Make ahead: the gratin can be assembled the day before, covered in the fridge, and baked directly the next day by adding 5 extra minutes of cooking.
• Hearty variation: a few turkey bacon bits tucked between the vegetable layers make it a more generous complete meal.
Nutrition Facts (per serving, estimated)
| 385 kcalCalories | 14gProtein | 12gCarbs | 32gFat |
