Vienna is lucky to have many beautiful blue skies with long sunny days in Summer at agreeable temperatures to make outdoor eating a pleasure. The food I prepared is usually light and seasonable, often served with a side salad. This Brie & Onion Tart is one of my favourite summer lunches. The pastry is amazingly buttery and uses chestnut flour, one that I never used until I went gluten-free. It has a deep nutty flavour, but once combined with other flours and the butter, it mellows and works very well in pastry tarts or pies. Chestnut flour is sold in health stores, but if you have a powerful food processor or better yet, a Thermomix ®, grind cooked chestnuts into a flour texture.

If you are interested in learning more about different gluten-free flours, you may find this link useful A Guide to Gluten-Free Flours, Starches & Blends.

For the Gluten-Free Pastry Base:


For the pastry:

  • 280g gluten-free flour (store-bought or homemade gluten-free flour blend
  • 60g chestnut flour
  • 150g unsalted butter, cut into small pieces
  • 70g mild cheddar, grated


  • 1 egg yolk & 1 tsp water (to use only as egg wash)

Step-by-Step Instructions

1. Rub the butter into the flours by hand or blitz in a food processor until butter has combined with the flours.

2. Add the cheese and knead the dough for a few minutes by hand or food processor.

3. When smooth and well-combined, cover and allow to rest for at least 30 minutes in the fridge.

4. Just before removing the pastry from the fridge, preheat the oven to 180°C/350°F.

5. Remove the pastry from the fridge and roll it out on top of a sheet of baking paper into a rectangular shape to fit in a long tart tin of 34 cm x 11 cm or a round quiche tin, 25 cm in diameter.

6. Transfer the pastry to the tin. The pastry will fall apart slightly at the edges. Don’t worry, a simple mending job of moulding loose dough into the edges will fix that. It will still look great when cooked.

7. Cover the pastry with baking paper then with pastry weights/dried beans in order to blind bake (Blind baking is to pre-bake the pastry in two stages: first with pastry weights and then without, so that the pastry is cooked before the filling is added).

8. Blind bake for 15 minutes. While the pastry base is baking, start preparing the Brie & onion filling.

9. Remove the tart tin from the oven and remove the baking paper as well as the weights/beans.

10. Prick the pastry base with a fork (this prevents the pastry from bubbling up and rising) and brush it with some egg wash to give a crispier finish.

11. Return the tart tin back to the oven to bake for another 15 minutes.

12. Allow to cool down for 15 minutes before adding the filling.

For the Brie & Onion Filling:

  • 5 white or yellow onions, sliced thinly
  • 4 tablespoons unsalted butter
  • 2 tablespoons red wine vinegar
  • 3 tablespoons brown sugar
  • 1 teaspoon nutmeg, ground
  • 300g Brie cheese, cut into even segments
  • 1 teaspoon fresh thyme leaves, chopped


  • A few sprigs of fresh thyme, for garnishing

Step-by-Step Instructions

1. Slice the onions thinly.

2. Melt the butter gently.

3. Add the onion and fry gently for 20 minutes, stirring occasionally.

4. When the onions look brown and transparent, add the vinegar and sugar. Cook for further 10 minutes. Be careful not to burn the onions when adding the sugar.

5. Add the nutmeg and thyme leaves.

6. Add the warm onions to the cooled pastry base.

7. Top with the Brie segments.

8. Bake for 10 minutes at 180°C/350°F. Bake longer if the Brie needs to melt more but don’t let the Brie completely disappear into the tart.

9. Allow to down cool slightly before serving.

10. Garnish with some fresh thyme sprigs.

This tart can be eaten cold with Dijon mustard and a freshly made side salad.

I had a tiny bit of pastry left-over, so I ended up filling a mini tin with some cream and the remaining egg wash, then topped it with a few pieces of Brie and some cherry tomatoes.

For me, this pastry recipe is excellent for so many summer quiches and tarts. I hope you enjoy making this tart and have fun coming up with your own filling ideas.