Sweet potato pies with marshmallow topping recipe

Ingredients

• 225 g plain (all-purpose) flour
• 1/2 tsp sea salt
• 2 tbsp caster sugar
• 160 g cold butter, diced
• 125 ml chilled water
• 3 large sweet potatoes, skins on
• 2 tbsp ground cinnamon
• 1 tsp ground mace
• 2 tsp ground ginger
• 1 tsp freshly grated nutmeg
• 1/2 tsp ground allspice
• 2 tsp sea salt
• 230 g light brown sugar
• 1 vanilla bean, split in half lengthways, seeds scraped
• 4 eggs
• 250 g tin sweetened condensed milk
• 90 g golden syrup or treacle, plus extra to serve
• 60 g pure icing sugar, sifted
• 60 g cornflour
• 1 tbsp liquid glucose
• 450 g caster sugar
• 3 egg whites
• 7 g sachet powdered gelatine