Apple filling:Heat butter in a medium frying pan over medium-high heat. Add apples. Cook, stirring occasionally, for about 2 minutes. Add brown sugar, ground cinnamon and cornflour. Cook, stirring occasionally, for 15 minutes or until tender and the mixture is dry. Remove from heat. Cool completely.
Apple momos:Place one teaspoon of apple mixture on the center of each wrapper. Brush edges with a little water. Fold and pleat edges to enclose the filling. (Watch video below for pleat design ideas). Place prepared momos on a tray lined with baking tray.
Place momos in a steamer lined with baking (parchment) paper. Cook, in batches, for 15-20 minutes or until cooked through. Transfer to a plate. Cover to keep warm.
Toffee sauce:Melt butter in a medium saucepan over medium-high heat. Stir in condensed milk, brown sugar, glucose syrup and water. Cook, stirring, until thickened. Remove from heat. Stir in vanilla extract.
Serve warm momos with warm toffee sauce.