French Mustard Tart Recipe

French Mustard Tart Recipe

I used to love my mam’s Mustard Tart (or Tarte a la moutarde as we call them in France) and these days it’s a fairly regular meal in my house. I serve it with or without tuna and it goes very well with a bowl of salad leaves with strong allium flavours on the side (think scallions or even a small clove of garlic grated in the vinaigrette). When you feel the need for something slightly stodgier, airfryer chips are really delicious with this tart. 

I make my own pastry because I treated myself to a Thermomix and it makes doing your own pastry stupidly easy but if you can’t make it, go for an all butter ready-made one if you can. I know it’s a little bit more expensive than the supermarket one but this is one of these times where spending a little bit more actually makes a very big difference to the overall dish.ย 


For the shortcrust pastry:

  • 150g plain flour
  • 75 frozen butter
  • 50 water

For the filling:

  • 1 heaped tbsp of dijon mustard, If you have a tarragon dijon even better
  • 1 large tin of tuna drained
  • 1 large handful of grated cheese (think a good cheddar or gruyere)
  • 1 large beef tomato. You want it nice and ripe. You can make this with any tomatoes really, just make sure they are fully ripe.
  • 1 tbsp of oregano
  • 1 egg for glazing the pastry 
  • black sesame seeds for garnish.  


  • Stick your butter in the freezer for an hour and then grate it directly into your flour and add the water and bring it all together quickly. The least you touch it the better. Tighten it all into a ball and wrap in cling film and place it in the fridge for a minimum of an hour. 
  • Preheat the oven to 180 C.
  • Roll out the pastry on a baking tray covered with baking paper and prick the bottom. 
  • Spread the mustard evenly on the bottom but leave about two inches on the outer edge as you will be folding that over later.
  • Add your drained tuna and then your grated cheese over the tuna.
  • Place your sliced tomatoes on top and sprinkle with the oregano
  • Fold the flaps over the contents and pinch to keep in place as per the photo below. 
  • Place in the oven for about 20 min or until the pastry is golden. 
Mustard Tart -
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