Apple tart

Pastry

• 75 g unsalted butter, diced plus extra for greasing
• 150 g plain flour, plus extra for dusting
• 1 pinch fine sea salt
• ½ tsp vanilla sugar, homemade
  或 ¼ tsp natural vanilla extract
• 50 g water

Topping

• 900 - 1000 g apples (e.g. Granny Smith, Braeburn, Pink Lady, Pippin)
• 30 g caster sugar
• 10 g unsalted butter, diced