Easy Vegetable Gratin (Get Your 5-a-Day!)

This Easy Vegetable Gratin is a delicious plant-based dinner recipe, loaded with 5 veggies, full of taste, and super creamy.

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I love to make large dishes for dinner, like my Vegan Sweet Potato Casserole, Vegan Spaghetti Squash Alfredo, or Quinoa Bake With Veggies, because they are not only delicious, but they are perfect to meal-prep many days of lunches or dinners.

Today, I wanted to make a similar casserole dish, but I wanted it loaded with many different kinds of veggies and full of a creamy sauce.

Ingredients and Substitutions

You need 5 veggies and a few ingredients for the bechamel to make this delicious dish. If you want even more veggies, you can swap the classic bechamel for my Cauliflower Bechamel.

• Cauliflower Florets – Cauliflower provides texture and flavors. You can swap with broccoli if preferred but it won’t be as creamy and melt-in-your-mouth.
• Sweet Potato – They add sweetness and color to the dish. Use butternut squash as an alternative.
• Mini Carrots – Peel and halve lengthwise to roast evenly. Baby carrots or chopped large carrots also work.
• Potatoes – Keep the potatoes unpeeled for a rustic feel. Yukon Gold or red potatoes are ideal for this recipe.
• Red Onion – Red onions add a mild sweetness. Swap with yellow onion for a more subtle taste or shallots for a fancy version.
• Garlic Head – Roasted garlic brings depth and richness to the béchamel sauce. I use a whole garlic.
• Garlic Powder, Paprika, Oregano, Salt – These enhance the roasted vegetables with earthy, savory notes. Adjust seasonings to taste. You can try thyme or rosemary for a different twist.
• Flour – All-purpose or gluten-free flour both work.
• Vegan Butter – Plant-based butter adds thickness to the sauce. You can also use margarine.
• Almond Milk – This is used to make the bechamel. Avoid sweetened non-dairy milks for a balanced flavor.
• Nutmeg – A hint of spice that is essential for the classic béchamel taste. If you don’t have any, skip it, don’t swap it.
• Dairy-Free Cheese – Mozzarella or cheddar-style vegan cheese melts well and adds creaminess.
• Panko Crumbs – These add some crunch to the topping. Use gluten-free panko if needed.

How to Make Easy Vegetable Gratin

This grating takes a wee while to bake, but there’s not much prep to get it going. Here are pictures of the key steps.

Slice all the veggies and place them in a large baking dish.

Spread the spices and drizzle some olive oil on the vegetables.

Bake the pan for 25-30 minutes at 430 °F (220 °C).

Meanwhile, [prepare the bechamel by melting vegan butter in a saucepan.

Gradually incorporate the flour before stirring the milk in the mixture.

Pour the bechamel over the roasted vegetables.

Stir the veggies until they are all coated in the bechamel sauce.

Add grated cheese and panko crumbs and bake again at  350 °F (180 °C) until the cheese has melted.

Serving Suggestions

• Pair It Up: Serve with a crisp green salad or a loaf of crusty bread to complement the creamy gratin.
• Great for Gatherings: This dish works as both a main course or a side, making it ideal for holiday meals or dinners.
• Make It Ahead: Roast the vegetables and prepare the béchamel in advance. Assemble and bake when ready to serve it.
• Flavor Additions: Add some sautéed mushrooms or roasted Brussels sprouts for a different flavor.

Expert Tips

Here are a few more tips to make this recipe perfect every single time.

1. Avoid Overcrowding the Baking Dish – Arrange the vegetables in a single layer for even roasting, if possible. This helps them develop a golden, caramelized finish.
2. Use a Large Baking Dish – An extra-large baking dish ensures better roasting and prevents the veggies from steaming.
3. Roast the Garlic Perfectly – Slice off the top of the garlic head and drizzle with oil to keep it moist. Roasted garlic will become soft and sweet—perfect for blending into the béchamel sauce.
4. Make a Smooth Béchamel – Warm the almond milk beforehand to avoid lumps, and whisk constantly while adding the milk to the flour mixture.
5. Blend the Sauce with Roasted Garlic – An immersion blender helps break the garlic into the sauce, ensuring its flavor is distributed evenly.
6. Golden, Crispy Topping – For extra crunch, lightly toast the panko crumbs before sprinkling them on the dish.
7. Bake Until Bubbly – Reduce the oven temperature after roasting the veggies. The gratin is done when the sauce bubbles, the cheese melts, and the topping turns golden brown.

More Veggie Dinner Recipes

Quinoa Bake with Veggies

Vegan Sweet Potato Casserole

Vegan Eggplant Rollatini

Miso Eggplant

Easy Vegetable Gratin

This Easy Vegetable Gratin is a delicious plant-based dinner recipe, loaded with 5 veggies, full of taste, and super creamy.

5 from 1 vote

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Prep Time: 50 minutes mins

Cook Time: 40 minutes mins

Total Time: 1 hour hr 30 minutes mins

Course: Dinner, Side Dish

Cuisine: American

Servings: 6 servings

Calories: 335.4 kcal

Author: Carine Claudepierre

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Ingredients

US Customary – Metric

• ▢ 4 cups Cauliflower Florets - about half a large head of cauliflower
• ▢ 1 large Sweet Potato - cubed
• ▢ 6 mini Carrots - peeled, halved lengthwise
• ▢ 3 small Potatoes - unpeeled, cut into quarters
• ▢ 1 Red Onion - sliced
• ▢ 1 Garlic Head - top sliced off
• ▢ 2 tablespoons Avocado Oil
• ▢ ½ teaspoon Garlic Powder
• ▢ ½ teaspoon Salt
• ▢ ½ teaspoon Paprika
• ▢ 1 teaspoon Oregano

For the Bechamel sauce

• ▢ ⅓ cup Flour - (note 1)
• ▢ 3 tablespoons Dairy-Free Butter (Unsalted)
• ▢ 2 ⅓ cups Warm Almond Milk - (note 2)
• ▢ ⅛ teaspoon Nutmeg
• ▢ 1 teaspoon Salt

To top up the dish

• ▢ ¾ cup Dairy-Free Grated Cheese - (note 3)
• ▢ ½ cup Panko Crumb - (note 4)

Instructions

• Preheat the oven to 430 °F (220 °C).
• Prepare your vegetable: cut cauliflower into florets, peel and slice the mini carrots in half lengthwise, cut the potatoes into quarters, peel and dice the sweet potatoes, slice the red onion, and cut off the top of the garlic head.
• Lay the vegetables randomly on the baking dish, except for the garlic. Make sure the veggies don't overlap too much – that's why I use an extra-large baking dish – they roast better this way.
• Sprinkle spices on top of the veggies: salt, garlic powder, paprika, and oregano.
• Drizzle avocado oil on top of the veggie and use your hands to massage the veggies and coat them evenly with the oil and spices.
• Place the garlic head somewhere on top of the veggies, in the middle of the dish, and drizzle a tablespoon of oil inside.
• Bake the veggies for 25-30 minutes at 430 °F (220 °C) until they are roasted and the garlic is soft.

Make the Bechamel

• Meanwhile, prepare the bechamel sauce. Pour the almond milk into a glass microwave-safe jug and microwave it for 1-2 minutes or until warm. Set aside.
• In a non-stick saucepan over medium heat, melt the vegan butter, then whisk in the flour until it forms a smooth paste.
• Gradually add the warm milk, whisking at the same time to dissolve the flour mixture into the warm milk.
• Bring the liquid to a light boil. You should see bubbles on the sides of the pan. Keep whisking gently to avoid the mixture from sticking to the bottom of the pan.
• When bubbles form, the bechamel should be thick and ready. Stop the heat and stir in salt and nutmeg. Set aside.

Assemble the vegetable gratin

• Remove the roasted vegetables from the oven, reduce to 350 °F (180 °C), and take the garlic head out of the dish. Let the garlic cool down for 10 minutes until you can handle it, then squeeze out the soft roasted garlic into the bechamel and discard it.
• Blend the bechamel with an immersion blender a few times to break the roasted garlic nicely into the sauce.
• Pour the bechamel over the roasted vegetable, sprinkle panko crumb and dairy-free cheese on top, and return to the oven until the sauce bubbles, the cheese has melted and the crumb is nicely golden.

Notes

Note 1: All-purpose gluten-free flour also works.

Note 2: Any non-dairy milk works, but I found soy milk or oat milk a bit sweet to make this sauce.

Note 3: Any hard, grated, dairy-free cheese works like cheddar or mozzarella-style cheese. 

Note 4: Use gluten-free panko crumbs if needed.

Storage: You can store leftovers in the fridge in an airtight container for up to 3 days or freeze them in a sealed container for up to 1 month. Thaw in the fridge the day before, then rewarm in the microwave.

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Nutrition

Serving: 1serving | Calories: 335.4kcal | Carbohydrates: 44.4g | Protein: 6.7g | Fat: 15.2g | Saturated Fat: 2.8g | Polyunsaturated Fat: 3.1g | Monounsaturated Fat: 6.7g | Trans Fat: 1g | Sodium: 988.2mg | Potassium: 804.4mg | Fiber: 6.6g | Sugar: 5.6g | Vitamin A: 8227.1IU | Vitamin B12: 0.02µg | Vitamin C: 52.2mg | Calcium: 189.5mg | Iron: 2mg | Magnesium: 50.9mg | Phosphorus: 127.1mg | Zinc: 0.8mg