Place the warm milk in a bowl and add the yeast and 1 tsp of sugar, mix well and leave for a few minutes.
Put the remaining sugar in a large bowl and beat together with the butter and vanilla extract, using a hand mixer, until light and creamy.
Add lemon and orange zest and mix.
Add the eggs a little at a time until all are well incorporated.
If the mixture starts to curdle, add a tablespoon of the flour and beat in with the eggs.
Place the flour in a large bowl and mix with a pinch of salt and make a well.
Add the yeast mixture then the butter and egg mixture, folding in with a large spoon to make a soft dough.
Knead for 5 mins in the bowl until the mixture starts to come together and is pretty sticky.
Put the dough onto a floured surface and knead for a further 10 mins, until everything has come together and you get a soft, stretchy dough. Add a light sprinkling of flour to the surface and your hands as you go to stop the mixture sticking.
Place in a lightly greased bowl and cover with plastic wrap; keep in a warm place for 2 hrs or until it doubled in size.
Place the raisins in a small saucepan with the rum extract and heat on low for about 5 mins or until the fruit has absorbed the liquid; set aside to cool.
When the dough is risen, tip it out onto a lightly floured surface and knead for another 5 mins. Gradually knead in the soaked raisins and chopped candied peel. Shape the dough into a ball and pop into the prepared Panettone pan. If using an 8" deep cake pan, wrap a layer of baking parchment around the outside of the tin, to come up about 2" above the rim, and secure the paper with string. This will help contain the dough as it rises.
Cover lightly with plastic wrap and leave to rise for another hour until it has risen to the top of the pan or paper.
Preheat the oven to 350 F
Mix together the icing sugar and egg white and gently brush over the top of the Panettone.
Place the Panettone in the oven and bake for 40 - 50 mins or until golden and risen. Insert a skewer into the middle of the cake to test if done.
Leave to cool in the pan for 10 mins before turning out onto a cooling rack.
Leave to cool completely before dusting with icing sugar.