Caramelized Onion Tart with Gruyere and Thyme

Introduction

Caramelized Onion Tart with Gruyere and Thyme is a savory, satisfying dish that quickly became a family favorite in our home. The combination of rich, caramelized onions with the creamy Gruyere cheese and fragrant thyme makes for a mouthwatering treat that is perfect for any occasion. Whether you’re looking for an elegant appetizer to serve at a dinner party, a side dish for a special meal, or just a simple snack for the family, this tart is a winner. We’ve made it several times now, and it always garners rave reviews from both family and friends. The sweetness of the caramelized onions and the depth of flavor from the balsamic vinegar creates a deliciously complex filling that pairs beautifully with the crispy, flaky pie crust. Everyone agrees that this is one of those dishes that you could happily eat over and over again!

Why You’ll Love This Caramelized Onion Tart with Gruyere and Thyme

This Caramelized Onion Tart with Gruyere and Thyme is one of those dishes that has the perfect balance of flavors and textures. The sweetness of the onions, enhanced by the balsamic vinegar, contrasts wonderfully with the richness of the Gruyere cheese. The earthy thyme adds a touch of freshness, elevating the entire dish. The pie crust, when blind baked, becomes golden and crisp, providing the perfect base for this savory tart. It’s versatile enough to be served at any meal—whether as an appetizer, main dish, or a side dish. Here are just a few reasons why you’ll love this recipe:

• Perfect balance of flavors: The caramelized onions, Gruyere cheese, and thyme combine to create a rich and complex flavor profile.
• Flexible serving options: This tart can be enjoyed warm, at room temperature, or even cold, making it perfect for any occasion.
• Simple ingredients, sophisticated result: With just a few ingredients, you can create a dish that feels elegant and impressive.
• Comforting yet refined: It’s the ideal comfort food for a cozy dinner or a sophisticated appetizer for a dinner party.
• Make-ahead friendly: The tart can be prepared in advance, making it perfect for busy days when you want a delicious homemade meal.

Ingredients

For the Tart:

• 1 pie crust, preferably homemade (blind baked)
• 4 large onions, sliced into ¼-inch rounds
• 1 tablespoon sugar
• ½ teaspoon kosher salt
• 1½ tablespoons balsamic vinegar
• 2 tablespoons fresh thyme, chopped (or 2 teaspoons dried thyme)
• ¼ teaspoon freshly ground black pepper
• ¼ cup heavy cream
• 1 cup Gruyere cheese, grated

Instructions

Step 1: Blind Bake the Crust

Start by preparing your pie crust. If you are using a homemade crust, follow the instructions for blind baking. Once baked, allow it to cool completely before adding the filling.

Step 2: Caramelize the Onions

In a large frying pan, heat 2 tablespoons of olive oil over medium heat. Add the sliced onions, sugar, and salt. Stir occasionally to avoid burning, and cook until the onions reduce to about two-thirds of their original volume. This process will take approximately 30 minutes. If the pan seems dry, add a tablespoon of butter to keep things moist and prevent sticking. After this, stir in the balsamic vinegar and reduce the heat to low. Continue cooking for another 15 minutes, stirring frequently, until the onions are golden brown and fully caramelized.

Step 3: Add Flavor

Remove the pan from heat and stir in the chopped thyme and freshly ground black pepper. Allow the mixture to cool slightly before stirring in the heavy cream. Make sure everything is well combined.

Step 4: Assemble the Tart

Preheat your oven to 350°F (175°C). Spread the caramelized onion mixture evenly into the blind-baked tart shell. Sprinkle the grated Gruyere cheese evenly over the top of the onions.

Step 5: Bake

Place the tart in the preheated oven and bake for about 15 minutes, or until the filling is set and the cheese is melted and bubbly.

Step 6: Serve

Let the tart cool slightly before serving. You can serve it warm or at room temperature, and garnish with a sprig of thyme for a nice finishing touch.

Nutrition Facts (Servings and calories per serving)

• Serving Size: 1 slice (1/8th of the tart)
• Calories: 350
• Total Fat: 25g
  • Saturated Fat: 9g
  • Trans Fat: 0g
• Cholesterol: 40mg
• Sodium: 470mg
• Total Carbohydrates: 29g
  • Dietary Fiber: 3g
  • Sugars: 8g
• Protein: 6g

(Note: These values are approximate and will vary based on the specific ingredients used.)

Preparation Time

• Prep time: 25 minutes
• Cook time: 1 hour (includes time to caramelize onions)
• Total time: 1 hour 25 minutes
• Yield: 8 servings (1 tart)

How to Serve

This Caramelized Onion Tart with Gruyere and Thyme can be served in a variety of ways:

• As an appetizer: Serve slices of the tart on a platter at a party or gathering.
• As a main course: Pair with a fresh green salad for a light and satisfying lunch or dinner.
• As a side dish: Serve alongside roast meats or poultry for a hearty, flavorful side.
• For brunch: Serve warm or at room temperature with a side of scrambled eggs or roasted vegetables.
• For picnics or packed lunches: The tart can be enjoyed cold or at room temperature, making it ideal for a picnic or to take for lunch.

Additional Tips

1. Make sure to caramelize the onions slowly: The key to getting perfect caramelized onions is patience. Don’t rush the process. Low and slow is the way to go.
2. Use high-quality Gruyere cheese: The quality of the cheese will greatly impact the flavor of the tart, so choose a good Gruyere that melts well.
3. Blind bake your crust thoroughly: Blind baking ensures that the crust stays crisp and doesn’t become soggy from the caramelized onion filling.
4. Make it ahead of time: You can prepare the tart in advance and store it in the refrigerator for up to two days. Reheat it in the oven for a few minutes before serving.
5. Customize the filling: If you prefer, you can add other herbs like rosemary or sage for extra flavor. You can also experiment with different cheeses like goat cheese or cheddar.

FAQ Section

1. Can I use store-bought pie crust?
   • Yes, you can use a store-bought pie crust if you’re short on time. Just be sure to blind bake it before adding the filling.
2. How can I make this recipe vegetarian?
   • This recipe is already vegetarian! Just ensure that you’re using a vegetarian pie crust.
3. Can I substitute Gruyere cheese?
   • Yes, you can substitute Gruyere with other cheeses such as Swiss, cheddar, or Fontina.
4. How do I store leftovers?
   • Store leftover tart in an airtight container in the refrigerator for up to 2 days. Reheat it in the oven before serving.
5. Can I freeze the tart?
   • Yes, you can freeze the assembled tart before baking. Wrap it tightly in plastic wrap and aluminum foil, and freeze for up to 3 months. Bake from frozen, increasing the baking time by 10-15 minutes.
6. Can I make this tart without balsamic vinegar?
   • If you don’t have balsamic vinegar, you can substitute it with red wine vinegar or apple cider vinegar for a slightly different but still delicious flavor.
7. How do I know when the onions are caramelized?
   • The onions are caramelized when they are golden brown and soft, with a sweet, rich flavor. They should have reduced in volume by about two-thirds.
8. What should I serve with this tart?
   • The tart pairs well with a green salad, roasted vegetables, or a simple soup. For a heartier meal, serve with grilled meats or poultry.
9. Can I make the caramelized onions ahead of time?
   • Yes, you can caramelize the onions up to 2 days in advance and store them in the fridge. Just warm them up before assembling the tart.
10. Can I use frozen onions for this recipe?
    • While fresh onions yield the best results, you can use frozen onions if necessary. Just be sure to thaw and drain them well before cooking.

This Caramelized Onion Tart with Gruyere and Thyme is an irresistible dish that combines deep, savory flavors with a buttery, flaky crust. Whether you’re hosting a party or preparing a cozy dinner at home, this tart is sure to impress!

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