Caramelised onion and mustard tart recipe

By Simon Rimmer

  1. Serves 6
  2. Takes 45 minutes to make, 45 minutes to bake, plus chilling
  3. Rating

This moreish dish is perfect for a wintry day as its warming flavours keep the cold away.

tried and tested
Caramelised onion and mustard tart


  1. 50g butter
  2. 1 tbsp oil
  3. 4 large Spanish onions, sliced
  4. 1 garlic clove, crushed
  5. 2 medium eggs and 2 medium egg yolks
  6. 50g wholegrain mustard
  7. 142ml carton double cream
  8. 2 tbsp chopped fresh mint leaves
  9. For the pastry
  10. 225g plain flour, plus extra for dusting
  11. 100g butter, cubed
  12. 25g caster sugar
  13. 1 medium egg, beaten


  1. 1. Pulse all the pastry ingredients together in a processor – add a dash of water so it comes together. Shape into a ball, wrap in cling film and chill.
  2. 2. Meanwhile, melt the butter and oil together in a large frying pan over a medium-low heat. Add the onions and garlic. Season and cook for 30 minutes, stirring often, until golden. Set aside.
  3. 3. Preheat the oven to 200°C/fan180°C/gas 6. Roll out the pastry and use to line a 23cm x 3cm deep fluted, loose-bottomed tart tin. Fill with baking paper and beans, and bake for 15 minutes. Remove the paper and beans, and bake for a further 10 minutes, until golden.
  4. 4. Lower the oven temperature to 180°C/fan160°C/gas 4. In a bowl, whisk together the eggs, yolks, mustard and cream. Stir in the onions and mint. Season, spoon into the tart case, and bake for 20 minutes, until just set. Cool slightly, then remove and serve.

Nutritional info

Per serving: 574kcals, 41.8g fat (22.7g saturated), 10.7g protein, 41.9g carbs, 10.5g sugar, 0.9g salt


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April 18

This is yummy! I swapped some of the flour for wholemeal which made it a tad more filling. I also reduced the amount of cream.


June 30

I would pefer a little less mustard.


October 28

I made this for friends, and they all really loved it! I'll definately make it again.


April 1

my first onion and mustard tart so i can't compare but this is absoutely delicious - even better cold the next day!

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