Caramelised onion and mustard tart

A big 'meaty' dish that's great for lunch; it has sweet, strong onions, the sharpness of the mustard and crisp shortcrust pastry
By Simon Rimmer
Caramelised onion and mustard tart
  • Rating:
  • Serves: 6
  • Cook Time:
  • Prep Time: 20 minutes plus 1 hr 20 mins chilling time
  • Effort: easy


For the pastry

  • 225 g plain flour, plus extra for dusting
  • 75 g chilled butter
  • 1 pinches salt
  • 50 ml milk
  • 1 egg yolks

For the filling

  • 50 g butter
  • 1 tbsp vegetable oil
  • 4 large Spanish onions, sliced
  • 1 clove garlic, crushed
  • 2 whole eggs, plus 2 egg yolks
  • 2 tbsp grain mustard
  • 150 ml double cream


1. To make the pastry, put the flour, butter and salt in a food processor and pulse until 'crumbly'. Add the milk and egg yolk and pulse until a dough forms.2. Turn the dough out onto a lightly floured surface and knead for a few minutes, then wrap in cling film and chill for at least 1 hour.3. Roll out the pasty on a lightly floured surface to fit a 20cm tart tin, chill for 20 minutes.4. Preheat the oven to 200?C/gas 6. Bake the pastry case for 25-30 minutes until crisp and dry.5. Meanwhile, melt the butter and oil together in a medium pan over a low heat, then add the onions and garlic and season. Cook the onions very slowly for 30 40 minutes until golden.6. In a mixing bowl, whisk together the whole eggs, egg yolks, mustard and cream and stir in the cooked onions. Remove the tart from the oven and reduce the heat to 180?C/gas 4. Spoon the filling into the tart case and bake for 20 minutes until set, firm and golden.

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