Decadent Cheese and Onion Tart with Balsamic Caramelised Onions and Spelt and Parmesan Crust

There’s something undeniably satisfying about a well-made cheese tart. The creamy filling, the flaky crust, and harmonious flavours come together to create a dish that feels like a warm hug on a plate. Recently, I stumbled across a recipe for a German onion pie on Pinterest that piqued my interest. Whilst it didn't look like the traditional German onion pies that I have seen, I was taken by the image of a creamy cheese tat, generously loaded with an irresistible tumble of golden caramelised onions. While the Pin lacked detailed instructions, on how to make it, it ignited my creativity. I love nothing more than working out how something was made and using that as inspiration to create a dish of my own. This recipe can in no way be called a German Onion Pie, but this is my version of a cheese and onion tart that has its own character and flair, that I am happy to be able to share with you. Hopefully my decadent Cheese and Onion Tart with Balsamic Caramelised Onions and Spelt and Parmesan Crust will become a firm favourite of yours too.

The Crust Matters: Spelt and Parmesan Magic

Every great tart begins with a solid crust. In this recipe, I chose to craft my own version using wholemeal spelt flour combined with grated Parmesan cheese. The nutty flavour of spelt marries beautifully with the cheese's sharpness, resulting in a extra boost of cheesiness.

Once you have made your dough, it's important to wrap it in plastic and refrigerate it for 30 minutes. This crucial resting step allows the gluten in the flour to relax, which helps prevent shrinkage during baking.

The Creamy Filling: A Cheesy Delight

Staying true to the original recipe, I decided on a creamy mix of sour cream and Gruyere cheese. The sour cream adds a tangy sweetness that enhances the nutty cheese exceptionally well.

Sweet Balsamic Caramelised Onions: The Star of the Show

Now let’s discuss the onions, which are the shining stars of this tart. I opted for red onions instead of standard white onions. They not only add vibrant colour but also a natural sweetness which I enhanced further by adding balsamic glaze.

Cheese and Onion Tart with Balsamic Caramelised Onions and Spelt and Parmesan Crust - The Recipe

Ingredients

For the Crust:

100g butter

200g Wholemeal Spelt Flour

50g Finely grated parmesan

Pinch of Salt

8-9 tbsp cold water

For the Balsamic Caramelised Red Onion Topping:

4 large red onions, chopped

3 tbsp oil

50 g butter

2 Cloves of garlic, finely minced

Pinch of salt

4 tbsp Balsamic glaze

For the Sour Cream Filling:

3 eggs

125ml soured cream

100g Gruyere cheese, grated

salt and pepper

Method

Pre-heat the oven.190°C, Fan 170°C, 375°F, Gas 5

Rub a little butter around the inside of a 23cm/9” quiche dish or tin.

Chop the butter into small cubes and place in to a mixing bowl along with the flour and grated parmesan.

Rub the butter, cheese and flour lightly between your fingers tips until the mixture looks like breadcrumbs. Gradually add enough water to form a soft dough.

Cover and rest it for 15 minutes in the fridge. It's important to rest the dough to avoid the pastry shrinking in the oven.

Meanwhile, heat the oil in a large frying pan over a medium heat and add the onions. Cover and cook, stirring the onions occasionally until the onions are soft and starting to caramelise which will take 20-25 minutes.

Add the garlic towards to very end of cooking and stir in to cook for for a few minutes. Stir in the balsamic glaze and continue to stir for 5 minutes. Remove from Heat and set aside.

Dust the work surface with flour, put the dough in the middle and sprinkle it with flour.

Roll out the pastry 5cm/2” larger than your dish and lift it into the dish, OR simply press it into the baking dish using your fingers. Cut away any pastry that hangs over the edge of your dish.

in a separate bowl whisk together the eggs, soured cream and cheese. Season with salt and pepper.

Pour the soured cream mixture in the case. Put the tart into the oven and cook for 25 to 30 minutes, until the tart is set with a slight wobble.

Remove from the oven and tumble on the red onions on top of the tart using a slotted spoon to drain any excess oil. Return to the oven for 10 minutes

Once out of the oven, allow the Gruyere tart to cool for about 10 minutes. This resting period helps the filling set, making slicing easier.

Try to resist cutting into your creation too soon — it’s tough, I know! But that patience pays off when you take your first bite. You’ll savour the nutty crust's crunch, the cheesy richness, and the sweetness of the balsamic onions. This flavour combination is perfect for any occasion, whether hosting a dinner party or enjoying a cosy night in.