Vegetable Au Gratin

5 from 11 votes

My Vegetable Au Gratin recipe combines crisp-tender vegetables baked in a creamy, cheesy sauce and topped with golden breadcrumbs and parmesan. It’s simple to make in under an hour and works wonderfully as both a side dish or a hearty vegetarian main. Even the kids love it!

Prep Time10

Cook Time45

Total Time55

Course: Side Dish

Cuisine: American, Italian

Diet: Vegetarian

Servings: servings

Calories: 251kcal

Author: Anjali Shah

Equipment

Ingredients

4 tbsp butter
¼ cup all-purpose flour
2 cups low-fat milk
1⅓ cup grated cheddar cheese
½ tsp nutmeg
½ tsp salt
½ tsp pepper
1 head of broccoli cut into florets
½ large cauliflower cut into florets
4 carrots peeled and sliced
⅔ cup panko crumbs
⅓ cup grated parmesan cheese

Instructions

Preheat the oven to 340 degrees F / 170 C.
Melt the butter in a medium pot over a medium-low heat.
When melted sprinkle in the flour and stir to combine, cook on low heat for 2 minutes.
Add ¼ cup of milk at a time, stirring in between each addition to ensure there’s no lumps.
When all the milk has been added continue to cook for another 2 minutes, stirring continuously.
Add the cheddar cheese, nutmeg, salt and pepper. Stir for 3-4 minutes until well combined and cheese is fully melted, adjust seasoning to taste. Remove from the heat.
In a large oven dish add the vegetables in an even layer, cover with the cheese sauce, stirring gently to ensure the vegetables are coated in the sauce.
Sprinkle the panko crumbs and parmesan cheese over top of the vegetables.
Bake in the oven for 30-35 minutes. The topping should be a lovely golden color and the vegetables should be tender.
If the vegetables need to be cooked a little longer cover the baking dish with foil and continue to cook for a further 5-10 minutes until completely cooked through, do not over cook.
Serve immediately or store leftovers in the fridge for up to 4 days.

Video

https://youtu.be/71gEAw0Pe8o

Notes

I discovered when making veggies au gratin is to pre-cook the vegetables slightly before layering them in the casserole dish. I’ll steam or blanch tougher veggies like carrots, broccoli, or cauliflower for just a few minutes to soften them up. This ensures that all the veggies cook evenly and come out perfectly tender by the time the cheese sauce is bubbly and the top is golden. Plus, pre-cooking helps lock in the vibrant colors, making the casserole look even more appetizing!
I make sure to choose vegetables with low water content, like root veggies and cruciferous options, for the best texture. If I decide to use sliced zucchini, I salt it beforehand to release excess moisture, then pat it dry. This step ensures my au gratin won’t turn out watery.
Carefully measuring the flour, butter, and milk accurately for a smooth bechamel sauce is key. Too much milk will make the roux runny, and too much flour will make it thick and lumpy. The flour is cooked properly when it gives off a slightly nutty smell after cooking for about 1-2 minutes. Then, I incorporate the milk slowly while whisking to keep the sauce lump-free! Continuously whisking will ensure the roux is smooth and does not burn.
I’ll toss in some fresh thyme, rosemary, or chives to give the dish a subtle, earthy flavor. They blend beautifully with the cheesy sauce and add a nice touch of freshness.
Once it’s out of the oven, I let the casserole sit for about 10 minutes before serving. This helps the sauce thicken and settle, making it easier to slice and serve without losing its shape.
If I want an extra-crispy top, I switch the oven to broil for the last 2-3 minutes. Watching carefully, I let the breadcrumbs and cheese turn a deep golden brown for a perfect, crunchy finish.

Nutrition