Rub together (or pulse in a food processor) until you have a lump free crumb.
Add 2 tbsp cold water and cut it through with a round knife (or pulse the food processor) until the mixture clumps.
Gather the dough into a ball. If it's warm, wrap and chill in the fridge for 15 minutes.
On a lightly floured work surface, roll out the pastry to a few centimetres wider than the tart tin.
Pick the pastry up with the rolling pin and lift it into the quiche tin, carefully easing into the corners and up the sides.
Trim the pastry so that it's level with the top of the tin.
Prick the base all over with a fork.
Line with baking paper and then fill with baking beans.
Bake for 15 minutes, then remove the paper and baking beans and bake for a further 5 minutes until the base looks dry.
Make The Caramelised Onions
Sauté the onions with a bit of olive oil in a saucepan over a medium heat for 3-5 minutes until golden brown and soft.
As they begin to caramelise, add the salt and sugar and cook for about 10 more minutes on low, stirring occasionally so that they don’t burn. You can add a splash of water if they start looking dry.
Add the balsamic glaze and stir through.
Cook for a final 1-2 minutes.
Set aside too cool.
Complete Your Tarts
Spoon the caramelise onions into your tin.
Top with the crumbled goats cheese.
Whisk the cream, egg yolks and a pinch of salt and pepper in a jug.
Pour into the pastry case.
Bake for approximately 30 minutes or until golden brown and risen. Allow to cool for a few minutes, then once cool enough to handle, carefully release from the tin and check that the base is cooked.