White Onion Tarts


Prep time: 
20 minutes
Cooking time: 
60 minutes


Give onions centerstage in these yummy tarts that will melt in your mouth. Use store-bought short crust pastry for an easy time saver.


If making short crust pastry:

  • 450g plain flour
  • 225g unsalted butter, very cold and cut into chunks
  • 5g salt
  • 110g ice cold water

Tart filling:

  • 3 white onions, peeled
  • 100g butter
  • 100ml oil
  • Salt and Pepper
  • 250g double cream
  • 50ml milk
  • 15g grain mustard
  • 3 whole large eggs
  • 2 egg yolks
  • 30g pecorino cheese, finely grated


  1. If you are making your own pastry, start here. If not, start at step 3: Into the bowl of a food processor, weigh the flour and salt. Give the mixture a few pulses to stir it through. With the processor running, add the butter chunks a few at a time through the feeder tube. Once all the butter is incorporated, slowly add the ice cold water until the pastry just comes together. You may not use all of the water. 
  2. Turn the pastry out from the bowl and divide it in two and press in squares. Cover the pastry with cling film and rest in the fridge for 30 minutes.
  3. Preheat the oven to 200°C.
  4. On a lightly floured work surface roll the pastry out to 3-4mm thickness and use a 7cm in diameter cutter to cut out rounds. Line a muffin tray with the pastry rounds.
  5. Blind bake the pastry for 20 minutes, then set aside to cool. While the tart cases are cooling make the onion filling.
  6. Reduce the oven temperature to 120°C.
  7. Cut 8 slices of white onion in 5mm thick slices, heat a non-stick frying pan and caramelise the onion slices on both sides with half the butter and seasoning. Set the caramelised onion slices aside.
  8. Use a mandolin to slice the rest of the onions very finely.
  9. Heat the rest of the butter and cook the finely sliced onions until transparent with no colour. Season lightly. Place a lid on the pan to prevent the onions from colouring while cooking.
  10. Drain any excess butter and liquid.
  11. Add the cream and milk and bring the mixture to the boil and let the cream infuse. Let it sit for approximately 20 minutes to infuse and maximise the flavour.
  12. Whisk the eggs and add the eggs, grain mustard and finely grated pecorino to the cooled cream mixture, mix well.
  13. Pour the mixture into the prebaked tart cases to just below the rim, then gently place a slice of the caramelised white onion on top of the egg custard.
  14. Gently place the baking tray with the tarts in the preheated oven and bake for 35 - 40 minutes.
  15. Test the tarts by gently giving the tray a knock with the back of your hand. If the tarts are still wobbling continue cooking until they are set. Let the tarts cool on a wire cooling rack before serving.




Photo Credit: Jonny Hughes @jonny2love
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