Spring Vegetables Au Gratin
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This Vegetable Au Gratin is cozy, creamy, and just the right amount of indulgent. With layers of tender spring veggies and a golden, crispy cheesy topping, it’s right at home alongside my Roasted Carrots and Asparagus with Tarragon Butter or Lemon Dill Buttered Potatoes for an easy dinner spread.
Cozy, Creamy Vegetable Bake
Here’s the inside scoop—“au gratin” is all about that creamy base and golden, bubbly top. This version uses a classic Mornay sauce, which is just a simple béchamel made richer with melted cheese (aka the reason it’s so good).
It coats every layer in that silky, garlicky goodness, while the mix of baby potatoes, asparagus, fennel, and carrots keeps things feeling fresh and bright. Cozy meets fresh in the best way!
Why You’ll Love This Recipe
Key Ingredients
The Veggies and Cheese
Baby potatoes
Creamy and buttery, they hold their shape and give the dish some substance.
Asparagus
Adds freshness and a little snap to balance the richness.
Fennel
Subtle sweetness and that light anise flavor that makes it feel a bit more elevated.
Carrots
Bring color and natural sweetness.
For The Mornay Sauce
Gruyère + Parmesan
Nutty, melty, and just salty enough to carry the whole dish.
Heavy cream + milk
The base of that silky, garlicky béchamel-style sauce.
*Find the full printable recipe with specific measurements below.
Seasonal Produce Spotlight – Spring Vegetables
Spring in the Pacific Northwest always feels like a reset at the market—piles of just-harvested produce, bright colors, and that first wave of truly fresh flavors after winter.
Carrots
Sweet, earthy, and especially tender this time of year. Perfect for roasting, shaving into salads, or layering into cozy bakes like this one—or something like my hot honey butter roasted carrots.
Baby potatoes
Creamy and buttery with thin skins, they hold their shape beautifully and add just the right amount of richness.
Fennel
Lightly sweet with a subtle anise flavor, fennel brings a fresh, crisp contrast—whether thinly sliced or roasted until soft and caramelized. I love pairing it with fruit and greens, similar to my grapefruit avocado arugula salad.
Asparagus
The unmistakable sign of spring. Tender, grassy, and best when cooked simply—roasted, sautéed, or tucked into dishes like this gratin.
Step-by-Step Directions
1
Make the Roux
Melt butter in a medium saucepan over medium heat. Whisk in flour until smooth, cooking for 1-2 minutes while stirring.
2
Make the Sauce
Gradually stir in milk, cream, garlic, thyme, nutmeg, salt, and pepper. Simmer on low, stirring occasionally until smooth and slightly thickened.
3
Add Cheese
Lower the heat and mix in the Gruyère until melted and smooth. Adjust seasoning to taste.
4
Layer the veggies
In a large casserole dish, arrange half the sliced vegetables in an even layer.
5
Layer the Sauce
Pour half of the cheese sauce over veggies.
6
Finish Assembling
Add the remaining vegetables and cover with the rest of the sauce. Press down gently on the veggies to thoroughly distribute the sauce.
7
Add the Topping
Sprinkle Parmesan and breadcrumbs on top. Cover with foil and bake at 350°F for 40 minutes.
8
Bake the Gratin
Remove foil, continue baking for 20 more minutes until the top is golden brown and veggies are tender. Let stand briefly before serving, allowing the flavors to meld and the sauce to thicken slightly.
Pro Tips
- Slice veggies thin and evenly so everything cooks at the same rate, a mandoline works great for this
- Use good quality, freshly grated cheese for the smoothest sauce
- Add or swap leeks, mushrooms, or greens if you want to mix it up
- Use half-and-half instead of heavy cream for a lighter option
- Let it rest 10–15 minutes before serving so it sets up nicely
- Broil at the end if you want extra golden color on top
- Sprinkle fresh herbs like parsley or thyme before serving for a pop of color
What to Serve with Au Gratin Vegetables
Perfect for spring holidays like Easter or Mother’s Day, especially alongside:
Spring DINNER MAINS
- Pork Tenderloin with Strawberry Balsamic Sauce
- Herb-Crusted Cod with Lemon and Panko
- Lavender Herb Butter Roasted Chicken
Spring SAlAds
Party Tip: Make Ahead!
Prepare the veg au gratin until baking. Cover with aluminum foil and refrigerate overnight. Remove from the fridge 30 minutes before baking.
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Spring Vegetable Au Gratin Recipe
Equipment
- casserole dish (9×13)
- mandoline slicer (optional)
Ingredients
For the spring vegetables
- 1 pound baby potatoes, thinly sliced
- 1 large fennel bulb, thinly sliced
- 3 large carrots, peeled and sliced into thin rounds
- 1 bunch asparagus, trimmed and cut into 2-inch pieces
For the cheese sauce
- 5 tablespoons unsalted butter
- 5 tablespoons all-purpose flour
- 2 cups milk
- 1 cup heavy cream
- 2 cloves garlic, minced
- 1 tablespoon fresh thyme leaves (or 1 teaspoon dried)
- ½ teaspoon nutmeg
- 1 teaspoon kosher salt, plus more to taste
- ½ teaspoon fresh ground black pepper, plus more to taste
- 2 cups Gruyère cheese, freshly grated
For the topping
- 1 cup Parmesan cheese, freshly grated
- ½ cup panko bread crumbs (I used Italian herb seasoned panko but plain are good too)
Instructions
- Begin by melting butter in a medium saucepan on medium heat. Once melted, whisk in flour until the mixture is smooth. Continue stirring for 1-2 minutes to cook the flour slightly without browning it.
- Gradually add milk and cream to the saucepan, stirring constantly to prevent lumps. Add minced garlic, thyme, nutmeg, salt, and pepper, and let the sauce simmer on low heat. Stir occasionally until it thickens and begins to boil gently.
- Lower the heat and blend in the shredded Gruyère cheese until it's completely melted into the sauce, ensuring a smooth consistency. Taste and adjust the seasoning with additional salt and pepper if needed.
- In a lightly greased 9×13 inch baking dish, arrange half of your sliced vegetables in an even layer. Cover this layer with half of your cheese sauce, ensuring even coverage.
- Add the remaining vegetables in another layer and top with the rest of the cheese sauce, spreading it to cover all the veggies. Use a spatula or spoon to lightly press down the sauce into the vegetables to ensure it is evenly distributed.
- Evenly sprinkle shredded Parmesan over the sauce, followed by breadcrumbs for a crunchy finish.
- Cover the dish with aluminum foil and bake at 350°F for 40 minutes, allowing the vegetables to cook and the flavors to meld.
- Remove the foil and continue baking uncovered for an additional 20 minutes, or until the top is golden brown, the vegetables are tender, and the sauce is bubbly.
- Let the gratin stand for a few minutes after removing it from the oven. This resting period allows the sauce to thicken slightly for easier serving.
Recipe Notes
- Slice vegetables thin and evenly so everything cooks at the same rate (a mandoline works great here)
- If your veggies are thicker, roast them for 10–15 minutes first to ensure they soften properly
- Use freshly grated cheese for the smoothest, creamiest sauce
- Taste and adjust seasoning in the sauce before assembling—this makes a big difference
- Let the gratin rest for 10–15 minutes before serving so the sauce sets up
- For extra golden color, broil for the last 2–3 minutes (watch closely)
- Can be assembled up to 1 day ahead and baked when ready
- Leftovers reheat well in the oven, covered, until warmed through
Nutrition
*Nutritional information is provided as a courtesy only and should be construed as an estimate rather than a guarantee. Ingredients can vary and Maplevine Kitchen makes no guarantees to the accuracy of this information.
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