Heat the milk until lukewarm (about 90 degrees Fahrenheit or 37 degrees Celsius), add yeast with 1 tbsp brown sugar and stir to combine. Set aside for 15 minutes or until the yeast is foamy.
Combine all the flour, sugar, spices and salt in the mixing bowl. Gradually add the foamy yeast mixture into the dry ingredients, together with the softened butter and lightly beaten egg.
Using the dough hook with slow speed, start beating until the dry ingredients are moistened before increasing to medium speed and knead until the dough is silky smooth and elastic.
Gradually, add in candied and dried fruits and knead till well incorporated. Add more flour if the dough is slightly sticky.
Place the dough in a lightly greased bowl; turning the dough once to enable the top is lightly greased. Cover with plastic wrap and place in a warm spot to rise until almost doubled in size (about 50 to 60 minutes).
When the dough has doubled in size, gently punch it down to release the air, place the dough on a lightly floured surface and divide into 12 equal pieces.
Round each pieces against the tabletop and arrange onto a greased baking tray by having some spaces apart to allow room for proofing or doubling in size.
For egg wash, combine beaten egg, milk and salt and mix well. Brush the top of the buns with the wash and cover them lightly with oiled plastic wrap.
Allow the dough to rest and ferment in a warm place for another 50 to 60 minutes, until doubled in size or when touched lightly, the dough springs back halfway.
Preheat the oven to 200 degrees Celcius.
Prepare the topping for hot cross buns: In a mixer, combine the melted butter, milk, sugar, egg, vanilla extract and lemon zest and with the paddle attachment, mix all for one minute on low speed. Add the flour and continue to mix until homogenous and smooth. The topping is now ready to be filled into a piping bag and piped on top of the buns.
Brush the surface of the buns with another layer of egg wash before piping a cross (+) on top of the buns. (For those who do not like the idea of piping a cross, you may just wish to pipe a (Z) onto the buns.
Bake for 20 to 23 minutes until light golden brown.
Remove from the oven and place the tray on a cooling rack. Brush with melted butter for nicer finishing.