Measure flour into a medium mixing bowl. Rub cold butter through the flour until the mixture is pea sized. You can do this in a food processor. Add the sugar and pinch of salt and mix to combine. Add the eggs and yolk. Mix gently. Turn out onto a lightly floured surface and knead just until dough comes together. Cling film and rest for 20 minutes in the fridge.
Roll pastry out onto lightly floured surface and roll to the thickness of a coin.
Line your greased tart tin with the pastry. I used a 34 cm rectangle tart tin. Blind bake at 180c for 15 minutes. Brush the pastry shell with egg wash and return to the oven for a few
more minutes, until golden and crisp.
In a medium bowl mix the caramel condensed milk with the sea salt.
Spread a layer of caramel on the tart base.