Name: Asiago Creamy Baked Onions
Prep time: 10 min
Cook time: 40 min
Total time: 50 min
Cuisine: American
Ingredients: 4 large yellow onions, peeled and sliced into 1/4-inch rounds; Olive oil, for drizzling; 1/2 teaspoon fresh thyme, chopped; Salt and pepper, to taste; 1 cup heavy cream; 2 teaspoons Dijon mustard; 1/2 cup Asiago cheese, grated

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Asiago Creamy Baked Onions are one of those unexpectedly delicious side dishes I always find myself coming back to. Tender roasted onion rounds are smothered in a velvety, mustard-kissed cream sauce and topped with nutty Asiago cheese. It’s rich, savory, and perfectly comforting—ideal for pairing with roasted meats, holiday spreads, or even as a vegetarian main when I want something cozy and flavorful.

Why You’ll Love This Recipe

I love how this recipe takes simple onions and transforms them into something elegant and crave-worthy. Roasting brings out their natural sweetness, while the creamy Asiago sauce gives every bite richness and depth. It’s an easy recipe with minimal prep, yet it feels special enough for a dinner party. And the bubbling cheese on top? That’s the kind of golden finish I live for.

Ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

4 large yellow onions, peeled and sliced into 1/4-inch rounds
Olive oil, for drizzling
1/2 teaspoon fresh thyme, chopped
Salt and pepper, to taste
1 cup heavy cream
2 teaspoons Dijon mustard
1/2 cup Asiago cheese, grated

Directions

Preheat & Prep
I preheat the oven to 450°F (230°C), grease a baking dish, and arrange the onion slices in a single, even layer.
Roast the Onions
I drizzle the onions with olive oil, then sprinkle them with thyme, salt, and pepper. I roast them for 20 minutes until they’re soft and just starting to caramelize.
Make the Cream Sauce
While the onions roast, I heat the heavy cream in a saucepan over medium heat until it begins to simmer. Then I stir in the Dijon mustard and half of the Asiago cheese, letting it melt into a smooth sauce.
Assemble the Dish
Once the onions are roasted, I pour the creamy mixture over them and top with the remaining Asiago cheese.
Bake Again
I cover the dish with foil and bake for another 20 minutes until the onions are tender and the sauce is bubbling and cheesy.

Servings and timing

This dish serves 4 people. Prep time is about 10 minutes, and the total cook time is 40 minutes—20 minutes for roasting and another 20 minutes for baking in the sauce.

Variations

Swap the cheese: I’ve used Gruyère or Fontina in place of Asiago for a different flavor profile.
Add breadcrumbs: For a little crunch, I sprinkle toasted breadcrumbs on top before the final bake.
Mix in veggies: I sometimes layer in sliced mushrooms or roasted red peppers for extra texture.
Use red onions: They give the dish a slightly sweeter and deeper flavor.

storage/reheating

I store leftovers in an airtight container in the fridge for up to 3 days. To reheat, I place the onions in an oven-safe dish, cover with foil, and warm at 350°F until heated through. For a quicker option, I microwave them in 30-second bursts, but the oven keeps the texture and flavor better.

FAQs

Can I make this ahead of time?

Yes, I prepare and assemble the dish ahead, refrigerate it, and bake it just before serving. I just add a few extra minutes to the baking time if it’s coming straight from the fridge.

What does Asiago cheese taste like?

Asiago has a nutty, slightly sharp flavor—somewhere between Parmesan and cheddar. It melts beautifully and adds depth to creamy dishes like this one.

Can I use milk instead of cream?

I don’t recommend it. The cream is what makes the sauce rich and prevents it from separating during baking.

How do I make this dish vegetarian-friendly?

It already is! Just double-check the Dijon mustard and cheese if I’m strictly avoiding animal-based rennet.

Conclusion

Asiago Creamy Baked Onions are a side dish that always surprises me with how good they are. Sweet, tender onions wrapped in a decadent, cheesy cream sauce—it’s the kind of comfort food I reach for when I want something simple but indulgent. Whether for a weeknight dinner or a festive gathering, this bake brings elegance and warmth to the table.