This Caramelized Onion and Sweet Potato Tart is a delicious blend of sweet and savory flavors. The buttery crust is filled with soft sweet potatoes and rich caramelized onions.
I love it when the onions get that golden color; it adds a sweet touch that makes everyone smile! It’s perfect as a cozy meal or a fancy side dish for guests!
Key Ingredients & Substitutions
Tart Crust: Using a pre-made crust saves time, but homemade crusts can be flakier and more delicious. You can also use gluten-free crusts if needed.
Sweet Potatoes: These add natural sweetness. If you’re looking for a substitute, try butternut squash for a similar texture and taste.
Onions: I love using yellow onions for their natural sweetness when caramelized. Red onions work too for a slightly sharper taste.
Cheese: Gruyère adds richness. If you can’t find it, sharp cheddar or even mozzarella works well! For a nutty flavor, try Emmental.
Heavy Cream: You can use half & half if you’re looking to lighten it up, or substitute with coconut cream for a dairy-free option.
How Do You Get Perfectly Caramelized Onions?
Caramelizing onions takes time but it’s worth it for the flavor! For perfectly caramelized onions, follow these steps:
- Start with clean, thinly sliced onions.
- Heat your skillet on medium-low and add oil or butter.
- Add the onions and sprinkle sugar (if using) to enhance sweetness.
- Cook for 25-30 minutes, stirring occasionally, until they become soft and golden brown.
- If they start to stick, lower the heat or add a splash of water.
This gentle cooking method brings out their natural sugars beautifully!
Caramelized Onion and Sweet Potato Tart
Ingredients You’ll Need:
For the Tart:
- 1 pre-made or homemade tart crust (for a 9-inch tart pan)
- 2 medium sweet potatoes, peeled and sliced into 1/4-inch rounds
- 2 large onions, thinly sliced
- 2 tablespoons olive oil or unsalted butter (for caramelizing onions)
- 1 teaspoon sugar (optional, to aid caramelization)
- 3 large eggs
- 1 cup heavy cream or half & half
- 1 cup shredded Gruyère or sharp white cheddar cheese
- 1/4 cup crumbled blue cheese or goat cheese (optional for topping)
- Fresh thyme sprigs, for garnish
- Salt and freshly ground black pepper to taste
How Much Time Will You Need?
This recipe will take about 40 minutes to prepare and another 30-35 minutes to bake, plus 15 minutes of chilling for the tart crust. So, in total, you’re looking at around 1 hour and 30 minutes from start to finish, including caramelizing the onions and baking time. It’s well worth the wait for such delicious flavors!
Step-by-Step Instructions:
1. Prepare the Tart Crust:
If you’re using a pre-made tart crust, place it into a 9-inch tart pan, gently pressing it into the edges. Trim any excess dough hanging over the sides. To prevent it from puffing up while baking, prick the bottom with a fork and chill in the refrigerator for 15 minutes.
2. Preheat the Oven:
While the crust is chilling, preheat your oven to 375°F (190°C) so it’s ready when you’re done with the next steps.
3. Bake the Tart Crust:
Once chilled, line the crust with parchment paper and fill it with pie weights or dried beans. Bake for 15 minutes, then remove the weights and parchment paper and bake for an additional 5 minutes until it’s lightly golden. Take it out of the oven and set it aside.
4. Caramelize the Onions:
In a large skillet over medium-low heat, heat your olive oil or butter. Add the sliced onions and sprinkle in the sugar if you’re using it to help with caramelization. Stir occasionally and allow them to cook for 25-30 minutes until they are soft, golden brown, and beautifully caramelized. Set aside when done.
5. Cook the Sweet Potato Slices:
Prepare your sweet potatoes by lightly roasting or frying the slices to soften them a bit before adding them to the tart. To roast, arrange the slices on a baking sheet, drizzle with olive oil, and roast in the oven for about 10 minutes until they are just tender. Remove and let cool slightly.
6. Make the Custard Filling:
In a mixing bowl, whisk together the eggs, heavy cream, salt, and pepper until smooth. Stir in the shredded cheese to complete the custard filling.
7. Assemble the Tart:
Layer the sweet potato slices evenly over the baked tart crust. Spoon the caramelized onions over the sweet potatoes. Finally, pour the custard mixture evenly over the entire tart filling, allowing it to settle in nicely.
8. Bake the Tart:
Pop the assembled tart into the preheated oven and bake for 25-30 minutes or until the custard is set and the filling looks lightly golden on top.
9. Garnish and Serve:
Once it’s done baking, remove the tart from the oven. If you liked, sprinkle crumbled blue or goat cheese over the top. Add fresh thyme sprigs for a beautiful finishing touch. Allow the tart to cool slightly before slicing and serving. Enjoy every flavorful bite!
This delightful tart combines sweet and savory tastes, making it a perfect option for any occasion!
Can I Use Other Vegetables Instead of Sweet Potatoes?
Absolutely! You can substitute sweet potatoes with butternut squash, zucchini, or even sliced beets for a different flavor and texture. Just make sure to adjust the cooking time as needed to ensure they’re tender.
How to Store Leftovers?
Store any leftover tart in an airtight container in the refrigerator for up to 3 days. To reheat, place slices in a 350°F (175°C) oven for about 10-15 minutes until warmed through, or microwave in short intervals.
Can I Make This Tart Ahead of Time?
Yes! You can prepare the tart crust and caramelized onions ahead of time. Assemble the tart without baking, cover tightly, and refrigerate for up to 24 hours. Just bake it when you’re ready to serve!
Can I Make This Recipe Dairy-Free?
Definitely! Substitute heavy cream with coconut cream or any plant-based milk, and use dairy-free cheese alternatives. The tart will still be delicious with these substitutions!