1 large rectangle sheet puff pastry (375g/13oz) 1 egg yolk (mixed with 1 tsp cream 600 g fresh strawberries (1.3lb) 1 ½ tablespoons sugar 1 medium lemon 375 g full fat cream cheese, softened (12oz) ½ cup caster sugar (superfine sugar) (105g / 3.5oz) ½ cup thickened cream (heavy whipping cream), cold (125ml) 2 teaspoons vanilla extract