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Caramelised onion and mustard tart

Name: Caramelised onion and mustard tart
Yield: For 4-6 people
Cuisine: French recipes
Ingredients: 50g butter; 1 tbsp oil; 4 large Spanish onions, sliced; 1 garlic clove, crushed; 2 medium eggs and 2 medium egg yolks; 50g wholegrain mustard; 142ml carton double cream; 2 tbsp chopped fresh mint leaves; For the pastry; 225g plain flour, plus extra for dusting; 100g butter, cubed; 25g caster sugar; 1 medium egg, beaten

Published: 31 Mar 07
Updated: 18 Mar 24

This caramelised onion tart with shortcrust pastry is moreish. Adding mustard warms the tart up, so it’s perfect for a wintry day, or to have cold at a party.

Medium
April 2007

Test kitchen approved

For 4-6 people
Takes 45 minutes to make, 45 minutes to bake, plus chilling

This caramelised onion tart with shortcrust pastry is moreish. Adding mustard warms the tart up, so it’s perfect for a wintry day, or to have cold at a party.

Vegetarian recipes

Nutrition: per serving

Calories: 574kcals
Fat: 41.8g (22.7g saturated)
Protein: 10.7g
Carbohydrates: 41.9g (10.5g sugars)
Salt: 0.9g

For 6 people

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Ingredients

50g butter
1 tbsp oil
4 large Spanish onions, sliced
1 garlic clove, crushed
2 medium eggs and 2 medium egg yolks
50g wholegrain mustard
142ml carton double cream
2 tbsp chopped fresh mint leaves

For the pastry

225g plain flour, plus extra for dusting
100g butter, cubed
25g caster sugar
1 medium egg, beaten

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Method

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.
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.
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.

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.