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Herb crusted vegetable gratin in a white ceramic dish with golden rosemary-Parmesan breadcrumb topping on a wooden board

Herb Crusted Vegetable Gratin

A layered vegetable gratin with zucchini, potato, and tomato topped with a crisp rosemary-Parmesan breadcrumb crust, baked until golden.
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Prep Time 20 minutes
Cook Time 45 minutes
Total Time 1 hour 15 minutes
Servings: 4 servings
Calories: 295
Ingredients Method Notes

Ingredients
  

Vegetables
  • 400 g Yukon Gold potatoes peeled and sliced 3 mm thin
  • 350 g zucchini about 2 medium, sliced 3 mm thin
  • 300 g ripe tomatoes about 3 medium Roma or vine-ripened, sliced 3 mm thin
  • 1 medium yellow onion halved and thinly sliced
  • 3 cloves garlic minced
  • 3 tbsp olive oil divided
  • 1 tsp fine sea salt divided
  • 1/2 tsp black pepper freshly ground
Herb Crust
  • 60 g panko breadcrumbs about 3/4 cup
  • 50 g Parmesan freshly grated, about 1/2 cup
  • 1 tbsp fresh rosemary finely chopped
  • 1 tbsp fresh thyme leaves stripped from stems
  • 1 clove garlic minced
  • 2 tbsp olive oil
  • 1/4 tsp fine sea salt

Method
 

Prep
  1. Heat the oven to 200 C / 390 F. Brush a 9x13 inch baking dish generously with 1 tbsp olive oil.
  2. Place zucchini slices in a single layer on a paper towel-lined tray. Sprinkle with 1/4 tsp salt, rest 10 minutes, then pat dry with paper towels.
  3. Heat 1 tbsp olive oil in a small pan over medium heat. Add the sliced onion and a pinch of salt. Cook for 6 to 8 minutes, stirring occasionally, until soft and translucent but not browned. Add the minced garlic for the last minute until fragrant. Set aside.
Assemble
  1. Spread the softened onion and garlic evenly across the bottom of the oiled baking dish.
  2. Arrange the potato slices in a single overlapping layer on top of the onion base. Drizzle with 1/2 tbsp olive oil, season with 1/4 tsp salt and a few grinds of pepper.
  3. Add an overlapping layer of zucchini slices. Season lightly with salt and pepper.
  4. Finish with a top layer of tomato slices, slightly overlapping. Season with the remaining salt and pepper. Drizzle with the remaining 1/2 tbsp olive oil.
Herb Crust and Bake
  1. In a bowl, combine the panko, Parmesan, rosemary, thyme, minced garlic, 2 tbsp olive oil, and 1/4 tsp salt. Mix until the crumbs look evenly coated and clump slightly when pressed.
  2. Scatter the breadcrumb mixture evenly over the tomato layer. Press it gently with your palm so it adheres as a cohesive layer.
  3. Bake uncovered at 200 C / 390 F for 40 to 45 minutes, until the crust is deep golden brown and the potatoes are tender when pierced with a knife tip.
  4. If the crust is browning too fast before the 35-minute mark, lay a sheet of foil loosely over the top and remove it for the final 5 minutes.
  5. Remove from the oven and rest for 10 minutes before slicing and serving. The vegetables will set and the layers will hold cleanly when cut.

Notes

For a crispier base, par-bake the potato layer alone for 10 minutes before adding zucchini and tomato. This ensures the potatoes cook fully without over-softening the top vegetables.