Flourless Moist Chocolate Cake / Gluten Free / No Flour

Flourless Chocolate Cake (pan size 38 x 26 cm or 15 x 10 in) 1 cup = 240ml; 1 tbsp = 15ml; 1 tsp = 5ml 120g dark chocolate (1 cup) 30g unsalted butter (2 tbsp) 30ml milk (2 tbsp) 4 egg whites a pinch of salt 50g sugar (4 tbsp) 4 egg yolks 1 tsp vanilla extract (5ml)