This Roasted Vegetable Au Gratin is loaded with vegetables and cheese coated in white sauce. It is baked until the crust is melted and turns golden brown. This creamy, cheese-loaded au gratin tastes great with some soup and toasted bread. Let’s see how to make this super easy-baked dish to make your day special.
What is Roasted Vegetable Au Gratin
Gratin simply refers to a crisply baked top. That crusty top is often achieved by grated cheese and/or breadcrumbs. In today’s au gratin recipe, we are using both breadcrumbs and cheese to achieve the golden crust on top. Who doesn’t love some cheese-loaded comfort dish? I bet you can’t stop with one bite of this creamy au gratin. This classic French dish is buttery, rich and super simple too.
The first time I had this dish was in a famous restaurant in Chennai. I was extremely fascinated by the sight of this dish. Later, when I moved to Europe, I had the authentic version in a lot of restaurants and fell in love with it. Sometimes it was so hard to get a veggie-loaded au gratin. Restaurants in the city we lived in, mostly had au gratin filled with potatoes. It was just too heavy for me to consume. I wanted to include a bunch of veggies in this dish. That’s also how I started making this recipe at home.

We often look at such fancy recipes on the internet or at a restaurant and get super tempted. But the recipe may be too complicated to even give a try. This recipe is such an easy one that even a beginner can make it with limited effort.
Reasons to love this Au Gratin
Easy to prepare
Kid-friendly recipe
Simple ingredients
Perfect for parties/potluck
A great recipe to include vegetables in
Of course, it is loaded with cheese and is delicious. That’s enough reason to love it.
How to make it

Saute the vegetables in butter. Remove from pan when they are cooked ¾th.
Next, in the same pan, add some butter and saute onion and garlic. Once they turn slightly brown, add the flour.
Cook the flour till the raw smell goes.
Gradually stir in milk and cook until everything is nice and thick. You can add your seasonings at this point.
Switch off and add in some shredded cheese.
Add the vegetables to this sauce mixture.
Pour into a baking dish.
Cover with more cheese and some bread crumbs.
Bake until done and Serve!
How to cook the Vegetables for Au Gratin
You can either steam the vegetables, roast them in the oven or roast them on the stovetop. In this recipe, I have used beans, carrots, peas, cauliflower and zucchini. The vegetables should be chopped into even, bite-sized pieces so that they cook evenly. Today, we are cooking the vegetables on the stovetop, by sauteing them in little butter. I like the slight crunch that the vegetables retain while cooking this way. If you want your vegetables to be softer, go ahead and steam them.
You can also add Broccoli, Potatoes, and Sweet Corn to this recipe.

Tips to get the Perfect Sauce
To get the perfect sauce, the ratio of flour, butter and milk needs to be precise. We don’t want the sauce to be too thick or too runny. Also, we want enough dressing to coat the vegetables. So, if you are using more vegetables, you need to increase the amount of sauce. Make sure you cook the flour for a minute at least, so that the raw smell of the flour disappears. Make sure you don’t cook it on a high flame. The flour may burn soon.
The following important point of getting the perfect sauce is to make sure it’s smooth, creamy and lump-free. Add milk little by little and keep whisking the mixture, so that no lumps are formed. Today, we add onions and garlic to this sauce. You can add onion powder and garlic powder as well. Also, to make the authentic sauce, try not to omit the addition of nutmeg powder.

How to get the Crispy Golden Brown Top
A layer of cheese and some breadcrumbs on top of the vegetable and cream layer is what gives the crispy golden brown top. Today, we are using both of these ingredients to get the golden brown top. You can use any cheese – Cheddar, Mozzarella, or Grated Parmesan. I have added only Mozzarella Cheese today.
A generous addition of Breadcrumbs on the topmost layer gives a nice colour and texture to the dish. If you don’t have breadcrumbs in hand, don’t worry. Just leave it out. I have made this vegetable au gratin many times with just the cheese layer on top and it tastes equally good.
Serving Suggestions
Since this dish doesn’t have any spice of its own, I add some red chilli flakes on top while serving. It is absolutely optional.
Serve this Roasted Vegetable Au Gratin with some Garlic Bread, Toasted Bread, Soup or just as it is. Makes a great meal.

More Veggies Dishes that you may like
Butternut Squash Coconut Milk Soup
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Recipe Card

Roasted Vegetable Au Gratin
Ingredients
To Cook the Vegetables
- 3 cups Chopped Vegetables I used carrot, peas, beans, cauliflower, zucchini
- 1 teaspoon Unsalted Butter
- Salt a pinch
For the Sauce
- 3 tablespoon Butter around 60 gms
- 3 cloves Garlic finely chopped
- 1 medium Onion finely chopped
- 3 tablespoon All Purpose Flour
- 2 cups Milk
- ¼ cup Cheese
- 1 teaspoon Salt
- ½ teaspoon Pepper powder
- ¼ teaspoon Nutmeg Powder
For the Topping
- ⅓ cup Grated Cheese
- 3 teaspoon Breadcrumbs
Instructions
Cook the vegetables
- Heat butter in a pan. Once hot, add the cut vegetables and a pinch of salt.
- Saute the vegetables for a few minutes in the butter.
- Once the vegetables are almost cooked and turn slightly golden brown, transfer to another bowl and keep the vegetables aside.
Prepare the Sauce & Bake
- Heat butter in the same pan. When it melts, add the onion and garlic. Saute till golden brown. Now, add the flour. Cook for a minute till the raw smell of the flour goes away. Make sure the flame is at a low temperature.
- Add milk little by little into the flour till it thickens. Keep whisking and make sure the sauce is smooth and not lumpy. Add salt, pepper, nutmeg powder. Reduce the heat to low and simmer until the sauce thickens enough. Make sure you keep whisking frequently. This takes around 5 minutes. Switch off the flame. Add grated cheese. Mix and keep it aside.
- Add the vegetables to the sauce and mix well. Pour this into a baking dish. Sprinkle a generous amount of grated cheese and breadcrumbs on top of this layer.
- Bake in a preheated oven at 180C/350F for 20 minutes. Remove from the oven and serve hot.