This French-inspired Caramelized Onion Tart is bursting with flavor from juicy, caramelised onions, savory herbs, and sharp cheddar cheese. It’s simple to make with a homemade shortcut pastry, and pretty enough to serve at a dinner party.
Every time we go to one of the patisseries near our house for lunch I always have one of their caramelised onion tarts. I just adore caramelised onions and the combination of the creamy tart filling with the sweet onions is heavenly.
So when the other day I had a craving for a caramelised onion tart I decided to make my own. And it’s quickly become one of the most popular recipes on this blog!
While you’re here, don’t forget to grab a free copy of my Top 15 Reader-Favorite Recipes! It’s loaded with delicious vegetarian-friendly recipes that are surefire crowd-pleasers.
While I opted to make my own shortcrust pastry you can certainly use store bought. Careme make fantastic frozen pastry that are wonderful to keep on hand in your freezer.
However, if you’ve never made your own shortcrust pastry, and always thought it was too difficult, you would be surprised by how simple it really is.
All it involves is blitzing a few ingredients together in a food processor for a few minutes and refrigerating before rolling out. Really, it’s that easy.
I opted for a wholemeal pastry base, which adds a lovely crumbly nuttiness to the base which I think adds to the overall rustic quality of the tart much more than a white flour version.
For the filling the star of the show is onions, slowly caramelised to make the most of their beautiful sweetness. (If you love caramelized onions too, be sure to check out this French Onion Soup recipe too!)
And while 3 onions might seem a lot for the filling of the tart you will find that the onions will sweat down dramatically during the cooking process, so don’t be alarmed.
For the cheese component of the filling I suggest a strongly flavored cheddar – Collier’s make an amazing vegetarian Welsh Cheddar which I adore – or try goats cheese.
Serve the Caramelised Onion Tart warm or at room temperature with a simple lettuce salad, or something fancier like this Mushroom Lemon Lentil Salad.
And for more delicious recipes, don’t forget to grab a free copy of my Top 15 Reader-Favorite Recipes before you go!
Caramelised Onion Tart
- WHOLEMEAL SHORTCRUST PASTRY
- 1 3/4 cups wholemeal flour whole wheat, 250g
- 3/4 cup cold butter 180g
- 1 egg yolk
- 2 tbsp chilled water
- 3 large onions peeled and chopped
- 1 tbsp balsamic vinegar
- 1 tbsp brown sugar
- 1 tbsp butter
- 1 1/3 cups sharp cheddar cheese grated, 150 g
- 2 eggs
- 1 egg yolk
- 2/3 cup cream 150ml
- 1/4 cup milk 50ml
- 3 tsp thyme leaves picked
- salt and pepper to taste
- Begin by making the pastry. Place the flour and butter in a food processor and process until the mixture resembles bread crumbs. Add the egg yolk and water and pulse until the mixture begins to come together to form a ball. Turn the mixture out onto plastic wrap and shape into a disc. Refrigerate for 30 minutes.
- Remove the pastry from the refrigerator and roll out the pastry on a lightly floured bench or silicone baking mat until approximately 5mm thick. Line a 30cm loose bottomed tart tin with the pastry, making sure to press into the sides, and trim the excess. Refrigerate for 15 minutes.
- Preheat the oven to 180 celsius (355 Fahrenheit) and line the tart with baking paper and fill with baking weights or beans. Bake for 10 minutes before removing the baking paper and weights and baking for a further 5 to 7 minutes or until the base is dry and lightly golden. Set aside to cool.
- To make the caramelised onions, heat a large frying pan over a medium low heat and add the butter before adding the onions and reduce the heat to low. Cook for 10 minutes before adding the balsamic, 2 tsp of the thyme leaves and brown sugar. Cook for a further 10 minutes until caramelised. Set aside to cool.
- In a bowl add the eggs and egg yolk along with the cream and milk and whisk to combine. Season to taste.
- Place the onions in the base of the tart and spread evenly over the base. Sprinkle with the grated cheese before topping with the egg mixture. Finally, sprinkle with the remaining thyme leaves. Bake for 15 to 18 minutes or until the filling is just set.