Ingredients

  • 75 g butter, room temperature
  • 175 g plain flour
  • 50 g mature cheddar cheese, grated
  • 1 teaspoon mustard powder
  • 1 teaspoon cayenne
  • 12 teaspoon salt
  • 25 g butter
  • 800 g red onions, very finely sliced
  • 2 teaspoons dried sage
  • 6 tablespoons balsamic vinegar
  • 6 slices goat cheese
  • 1 pinch cayenne

Method

  • To make the pastry, rub together (or blitz) the butter and flour until it forms a breadcrumb-like consistency.
  • Add the cheese, mustard, cayenne and salt and mix together with just enough cold water to form a dough.
  • Cover and rest in the fridge for 20 minutes.
  • Roll out into your lightly-greased tin (or tins) and bake for 15-20 minutes until cooked but not coloured.
  • Cool on a wire rack.
  • To make the filling, melt the butter in a large pan then add the onions, sage and balsamic.
  • Cook very gently for 30 minutes, stirring regularly, until the onions are cooked through and all excess liquid has evaporated.
  • Allow the mixture to cool.
  • When you are ready to make the tart, place the pastry case back in the oven at 180C and allow to heat for five minutes.
  • Spoon the filling into the case and top with the goats cheese then bake for 20 minutes.