Nutella hot cross buns

Ingredients

• 1 teaspoon caster sugar
• 1 cup warm milk
• 2 teaspoons dried yeast
• 500g plain or strong (bread) flour
• 50g caster sugar
• 1 level teaspoon salt
• 1 teaspoon mixed spice
• 1 teaspoon cinnamon
• 2/3 cup dark chocolate pieces
• 1 egg (lightly beaten)
• 50g butter melted
• Filling
• ½ cup Nutella
• Cross Paste
• 3 tablespoons plain flour
• 1 tablespoon cooking cocoa
• 1 tablespoon caster sugar
• enough water to make a thick paste
• Glaze
• 3 tablespoons water
• 3 tablespoons caster sugar