Cut the apples in half and use a melon baller to remove the seeds. Keep the skins on the apples if you wish, they are delicious.
Place a heavy bottom saucepan on medium heat.
Add the butter, water and sugar and slowly cook to a dark golden caramel.
Remove the pan from the heat and add the Avallen slowly and gently swirl to combine.
Use a slotted spoon to remove apples from the caramel to a 23cm wide by 5cm deep oven proof pan (cast iron is lovely to use) and place in a ring.
Make sure that the apples are tightly packed together, in a single flat layer.
Pour the remaining caramel from the saucepan over the apples 2/3 of the way up the cast iron pan.
Place the cold pastry round on top of the apples, using a spoon to tuck the sides of the disc around the apples.
Prick the pastry with a fork 8-10 times and bake in a pre-heated 180°C
oven for 50-60 minutes or until the pastry is a dark, golden brown tone.
Remove from the oven and allow the tart to rest in the pan for 20-30 minutes on a cooling rack.
Place a larger serving plate over the pan and carefully invert onto the platter.
Gently lift off the pan and enjoy the beauty!