Zucchini and Potato Gratin: Crispy, Golden, No Fuss
Late summer hits that strange sweet spot: zucchini is everywhere, you’re slightly tired of salads, but turning the oven on still feels like a commitment. The farmers’ market haul is piling up on the counter — courgettes, waxy potatoes, a bunch of rosemary — and you want something that feels like a proper meal without a proper effort. But here’s the thing: most gratins ask for cream, cheese sauce, or a béchamel that takes longer than the dish itself.
This zucchini and potato gratin skips all of that. Thinly sliced vegetables, a garlicky Parmesan breadcrumb crust, a drizzle of olive oil — that’s it. It bakes to a deep golden crunch on top and stays tender underneath. Ready in about 55 minutes start to finish, it works as a side or a light main, and it keeps well in the fridge for two days.
Pro Tip
The most common mistake with this gratin: skipping the pre-salting step. Zucchini holds a surprising amount of water — roughly 95% by weight — and if you layer it straight into the dish, that moisture steams the breadcrumb topping from below and you lose the crunch entirely. Instead, toss your sliced zucchini with a pinch of salt, let it sit for 10 minutes in a colander, then pat it dry with a clean kitchen towel before layering. That one step is the difference between a soggy bake and a properly crispy top.
Use medium zucchini — the smaller ones have less water and better flavor than the oversized ones. For potatoes, go with a waxy variety like Yukon Gold or Charlotte: they hold their shape after 40 minutes in the oven. No Parmesan? Pecorino works, or a sharp aged cheddar if that’s what’s in your fridge — the gratin will taste slightly different but still deliver that salty, savory crust.
Zucchini and Potato Gratin: Crispy, Golden, No Fuss
4
servings20
minutes40
minutes280
kcal10
minutes1
hour10
minutesIngredients
2 medium zucchini (about 14 oz / 400g total), thinly sliced
3 medium waxy potatoes (about 1 lb / 450g total), peeled and thinly sliced
1 oz Parmesan, finely grated (about 30g)
5 oz stale bread or plain breadcrumbs (about 150g)
1/2 tsp garlic powder
1/2 tsp dried rosemary (or fresh, finely chopped)
3 tbsp extra-virgin olive oil, plus extra for the dish
Salt and black pepper to taste
Directions
- Salt the zucchini. Toss sliced zucchini with a pinch of salt in a colander and leave for 10 minutes — you’ll see small beads of water form on the surface, which is exactly what you want to draw out before baking.
- Make the breadcrumb mix. Combine breadcrumbs, Parmesan, garlic powder, rosemary, salt, and pepper in a bowl — the mixture should smell sharp and herby the moment the Parmesan hits the crumbs.
- Preheat your oven to 400°F (200°C). Lightly oil a 10-inch (26cm) baking dish and dust the base with a thin layer of the breadcrumb mix to prevent sticking and add crunch from the bottom up.
- Pat the zucchini dry. Use a clean kitchen towel and press firmly — the slices should feel noticeably drier and slightly firmer to the touch after this step.
- Layer the vegetables. Alternate zucchini and potato slices in the dish, slightly overlapping — this keeps the layers even and helps everything cook at the same rate.
- Top and drizzle. Scatter the remaining breadcrumb mix evenly over the top, then drizzle with 3 tbsp olive oil — you want every crumb lightly coated so it toasts rather than dries out.
- Bake for 40 minutes. The gratin is ready when the top is deep amber and the edges are pulling away slightly from the dish — tap the crust gently with a spoon and listen for a dry, hollow sound.
Variations
For a heartier version, tuck thin slices of smoked mozzarella between the vegetable layers before adding the breadcrumb topping — it melts into pockets that pull apart when you serve. If you want to keep it fully plant-based, swap the Parmesan for nutritional yeast (same quantity) and a pinch of smoked paprika for depth.
Serving Suggestions
Serve alongside a simple green salad dressed with lemon and olive oil to cut through the richness of the crust. A bowl of warm tomato soup turns this into a full weeknight dinner with almost no extra effort. It also works well next to roast chicken or grilled fish as a vegetable side.
FAQ
Can I make this gratin ahead of time?
Yes — assemble the whole dish up to 8 hours ahead, cover it with plastic wrap, and refrigerate. Add the breadcrumb topping just before baking so it stays crispy rather than absorbing moisture from the vegetables.
My breadcrumb topping came out pale and soft. What went wrong?
The most likely culprit is too much moisture from the zucchini — go back to the salting and patting-dry step and don’t skip it. Also make sure your oven is fully preheated before the dish goes in: a cold oven steams instead of roasts.
Can I use sweet potato instead of regular potato?
You can — sweet potato slices at the same thickness will cook through in roughly the same time, and they add a subtle sweetness that plays well against the savory crust. I’ve tested this version in my kitchen a few times and it works, though the texture is slightly softer. It does make you wonder how far you could take the vegetable swaps here — thinly sliced fennel, anyone?
