Baked Zucchini & Vegetable Medley Gratin

This vibrant gratin layers thinly sliced zucchini, onions, carrots, peppers, tomatoes, and mushrooms in a light, savory custard of eggs, milk, flour, and baking powder. A final sprinkle of cheese melts to a golden finish, binding the vegetables into a tender, sliceable casserole. Perfect for a cozy weeknight dinner, a hearty brunch, or a potluck contribution, its medley of textures—from crisp edges to creamy center—and layers of garden‑fresh flavor make it universally appealing.

Preparation, Cook, and Total Times

  • Preparation Time: 20 minutes (slicing, sautéing, mixing)

  • Cook Time: 45 minutes (baking and finishing)

  • Total Time: 1 hour 5 minutes

YIELD

Serves 6–8 as a main or 8–10 as a side.

Cuisine

Contemporary European‑inspired vegetable bake.

A Full List of Ingredients

For the Vegetable Layers:

  • 2 medium zucchini, thinly sliced

  • 1 onion, thinly sliced

  • 1 carrot, peeled and thinly sliced

  • 1 bell pepper, deseeded and chopped

  • 4 small tomatoes, quartered

  • 7–8 mushrooms, sliced

  • Salt and freshly ground black pepper, to taste

  • 2 Tbsp olive oil, divided

For the Batter:

  • 3 large eggs

  • 300 ml milk

  • 5 Tbsp all‑purpose flour

  • 10 g baking powder (about 2 tsp)

  • Pinch of salt and pepper

For the Topping:

  • 150 g hard cheese (e.g., cheddar or gruyère), grated

Step‑by‑Step Cooking Directions

  1. Preheat and Prep: Preheat oven to 180 °C (350 °F). Line a baking sheet or 9×13 inch dish with parchment paper.

  2. Season the Zucchini: Place sliced zucchini in a bowl, season with salt, toss, and let rest 10 minutes to draw out moisture. Squeeze gently and pat dry.

  3. Sauté the Onion: In a skillet over medium heat, warm 1 Tbsp olive oil. Add onion and cook until translucent, about 5 minutes. Transfer to a bowl.

  4. Cook Carrot & Pepper: In the same skillet, add 1 Tbsp oil, then carrot and pepper. Sauté 4–5 minutes until slightly softened. Remove and set aside.

  5. Add Mushrooms & Tomatoes: Sauté mushrooms 5–7 minutes until golden, season lightly with salt and pepper. Stir in tomatoes and cook 2 minutes. Remove from heat.

  6. Whisk the Batter: In a large bowl, whisk eggs, milk, flour, baking powder, salt, and pepper until smooth.

  7. Layer the Vegetables: On the prepared pan, arrange zucchini slices in an even layer. Scatter onions, carrots, peppers, mushrooms, and tomatoes evenly over the zucchini.

  8. Pour the Batter: Gently pour the egg‑milk mixture over the vegetables, allowing it to fill spaces.

  9. Bake: Place in oven for 30 minutes, until the batter is set at the edges.

  10. Add Cheese: Remove from oven, sprinkle grated cheese over the top, and bake an additional 5–10 minutes until melted and golden.

  11. Rest & Serve: Let rest 5 minutes before slicing. Serve warm.

Nutritional Information

(Per serving, approx.)

  • Calories: 200 kcal

  • Carbohydrates: 15 g

  • Protein: 9 g

  • Fat: 11 g

  • Fiber: 3 g

  • Sodium: 280 mg

The Origins and Popularity of the Recipe

Vegetable gratins trace back to French countryside cooking—layering garden produce under custard or cream and cheese. This modern spin uses a lighter egg‑milk binder and incorporates Mediterranean staples (olive oil, zucchini, pepper) for a fresh, health‑minded version. Its ease and adaptability have made it a staple on food blogs and family tables alike.

Reasons Why You’ll Love the Recipe

  • Colorful & Flavorful: A rainbow of veggies in every bite.

  • Minimal Hands‑On Time: Quick sauté and simple batter.

  • Make‑Ahead Friendly: Assemble ahead and bake later.

  • Vegetarian & Crowd‑Pleasing: Appeals to all palates.

Health Benefits

  • Vegetable Powerhouse: Provides vitamins A, C, and fiber.

  • Calcium Boost: Cheese adds bone‑friendly calcium.

  • Protein & Satiety: Eggs supply quality protein for lasting fullness.

  • Healthy Fats: Olive oil contributes heart‑healthy monounsaturated fats.

Serving Suggestions

  • With a crisp green salad dressed in lemon and olive oil.

  • Alongside grilled fish or roasted chicken for a complete meal.

  • With crusty bread to soak up any juices.

Common Mistakes to Avoid

  • Skipping Zucchini Drain: Leads to a watery bake—always pat dry.

  • Uneven Slicing: Use uniform thickness (3–5 mm) for even cooking.

  • Overbaking: Custard becomes rubbery—check at 30 minutes and remove when set.

Pairing Recommendations

  • Wine: A bright Sauvignon Blanc or light rosé.

  • Beer: A crisp pilsner or wheat ale.

  • Non‑Alcoholic: Sparkling water with a slice of lemon.

Cooking Tips

  • Room‑Temp Eggs & Milk: Ensures smooth batter.

  • Gentle Layers: Avoid packing veggies too tightly to let batter flow.

  • Rotate Pan: Halfway through baking for even browning.

Variations to Try

  • Spicy Kick: Add chili flakes or diced jalapeño.

  • Herb Infusion: Stir fresh thyme or rosemary into the batter.

  • Cheese Swap: Use feta or goat cheese for tang.

  • Gluten‑Free: Substitute flour with chickpea flour.

Similar Recipes to Try

  • Classic Potato Dauphinoise

  • Zucchini & Tomato Ratatouille

  • Mushroom & Spinach Strata

  • Vegetable Frittata

Ingredient Spotlight

  • Zucchini: Low‑calorie, high in vitamin C and water content—ideal for light bakes.

  • Mushrooms: Rich in umami and B‑vitamins; absorb flavors beautifully.

  • Eggs: Provide structure and protein, binding the bake together.

Conclusion

This Baked Zucchini & Vegetable Medley Gratin transforms simple ingredients into a show‑stopping dish. Its layers of garden‑fresh produce, light custard, and melted cheese strike the perfect balance of comfort and elegance. Whether you’re feeding family or entertaining friends, it’s a versatile recipe that delights every time.

Frequently Asked Questions

1. Can I substitute milk for cream?
Yes—whole milk keeps it lighter; cream yields a richer custard.
2. How do I prevent sogginess?
Salt and drain zucchini, and pat completely dry before layering.
3. Can I use frozen vegetables?
Thaw and drain thoroughly, then reduce bake time slightly to avoid overcooking.
4. What size baking dish works best?
A 9×13 inch or similar‑sized pan allows even distribution.
5. How do I reheat leftovers?
Warm in a 160 °C (325 °F) oven for 10 minutes or microwave individual slices.
6. Is this recipe dairy‑free?
Use dairy‑free milk and omit or replace cheese with a plant‑based alternative.
7. Can I assemble in advance?
Yes—cover and refrigerate up to 24 hours before baking.
8. Why add baking powder?
It lightens the batter, creating a tender custard texture.
9. What other cheeses can I use?
Gruyère, fontina, or mozzarella all work well.
10. How do I make it vegan?
Use flax eggs, plant‑based milk, and vegan cheese; ensure no animal‑derived ingredients.