Caramelised Onion Tart
This tart weaves together a simple collection of ingredients to create an elegant, mouthwatering result. Sweet caramelised onions mingle with a golden, flaky crust and a luxuriously creamy filling. It’s the culinary equivalent of comfort wrapped in sophistication. Here’s what goes into it:
- Yellow or sweet onions, chosen for their mellow, sugary depth
- A buttery tart crust for that rich, golden crunch
- Earthy thyme, fresh if possible, to add fragrant herbaceousness
- Eggs and cream to bind everything into a custardy dream
Choosing the Best Ingredients for Caramelised Onion Tart
Ingredient quality is everything. These selections bring the tart to life:
- Onions: Select firm, unblemished yellow or sweet varieties like Vidalia or Walla Walla
- Butter: Go for high-quality, unsalted butter—it enhances the crust’s richness
- Herbs: Fresh thyme is ideal—its vibrant green leaves and earthy aroma add freshness. Dried thyme works in a pinch
- Crust: Homemade or store-bought—choose versions with real butter and minimal additives
- Cheese: Gruyère adds a nutty richness. Alternatives like aged cheddar or goat cheese also shine
Ingredients
- 2 large yellow onions, thinly sliced
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 1 teaspoon fresh thyme leaves, chopped (or ½ tsp dried thyme)
- 1 teaspoon balsamic vinegar
- 1 pre-made tart crust (homemade or store-bought)
- 3 large eggs
- 1 cup heavy cream
- 1 cup grated Gruyère cheese
- Salt and freshly ground pepper, to taste
Instructions
Step 1: Caramelising the Onions
Great flavor begins here—patience is your secret weapon.
- In a wide skillet, melt butter with olive oil over medium heat.
- Add onions and a pinch of salt. Toss gently to coat.
- Let them slowly cook down, stirring every few minutes, for 30–40 minutes until deeply golden.
- Stir in thyme and balsamic vinegar. Cook an additional 2–3 minutes. Let cool.
Step 2: Preparing the Tart Crust
While onions cook down, prepare the crust for perfection.
- Preheat oven to 375°F (190°C).
- Roll out homemade dough or fit store-bought into a 9-inch tart pan. Trim edges neatly.
- Prick base with a fork.
- Line with parchment and fill with pie weights or beans.
- Bake for 15 minutes. Remove weights, then bake 5–10 minutes more until lightly golden. Let cool.
Step 3: Making the Filling
This is where the magic really comes together.
- In a mixing bowl, whisk eggs and cream until smooth.
- Fold in cheese, caramelised onions, salt, and pepper.
- Mix gently so every bite is infused with flavor.
Step 4: Assembling the Tart
Time to bring it all together.
- Pour filling into the cooled crust and spread evenly.
- Bake 30–35 minutes or until set and golden on top.
- Allow to rest a few minutes before slicing and serving.
Times, Calories & Servings
- Prep Time: 15 minutes
- Cook Time: 1 hour
- Total Time: 1 hour 15 minutes
- Calories: 350–400 per serving
- Servings: 8
Tips for the Best Flavors and Textures
- Low heat is essential when caramelising—rush it and you’ll lose the magic
- Keep the onions spaced in the pan for even browning
- Let the tart rest before slicing—it helps the filling firm up
Serving Suggestions
As an Appetizer
Cut into petite squares and serve warm or at room temperature. A bright salad with vinaigrette adds the perfect contrast.
As a Main Course
Pair with roasted seasonal vegetables or a grain-based salad like quinoa. Add a chilled glass of dry white wine for a well-rounded meal.
As a Side Dish
Serve alongside roasted lamb or grilled chicken—the savory richness adds depth to any protein.
Nutritional Information
- Calories: 350–400
- Protein: 9g
- Carbs: 34g
- Fat: 24g
- Vitamins: A, C, calcium-rich from onions and cheese
How to Store
Leftovers? Rare, but possible. Store slices in an airtight container in the fridge for up to 3 days. Reheat in a 350°F (175°C) oven until warmed through for best texture.
The Best Variations of Caramelised Onion Tart
- Vegetarian Boost: Add roasted red peppers, zucchini, or mushrooms for extra body
- Gluten-Free: Use a gluten-free crust or bake filling in a greased dish without a crust
- Dairy-Free: Swap in coconut cream and plant-based cheese
- Herb Swaps: Try rosemary or oregano for new aromatic twists
Frequently Asked Questions
- Can I freeze it? Yes—freeze before baking. Wrap well and bake from frozen, adding 10–15 minutes.
- Can I use different cheeses? Definitely. Mozzarella, cheddar, goat cheese, or feta all work beautifully.
- How do I avoid a soggy crust? Blind bake thoroughly and let it cool before adding the filling.
Conclusion: A Dish Worth Trying
This caramelised onion tart isn’t just food—it’s an expression of comfort, flavor, and timeless simplicity. Whether it stars as a starter, shines as a main, or supports as a side, it brings warmth and elegance to any table. It’s a dish that invites creativity and delivers satisfaction, bite after golden bite.
