Grease a panettone tin or a 20 cm deep cake tin, or use a panettone case.
Place the warm milk in a bowl and add the yeast and 1 tsp of sugar and leave for a few minutes.
Put the remaining sugar in a large bowl and beat together with the butter and vanilla extract until really light, creamy and pale.
Stir in the lemon and orange zest. Add the eggs a little at a time until all are well incorporated. Spoon in a tablespoon of the flour if the mixture starts to curdle and beat this in with the eggs.
Place the flour in a large bowl and mix with a good pinch of salt and make a well in the centre. 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 it all starts to come together. It will be a pretty sticky dough at this stage.
Turn out the dough onto a floured surface and knead for a further 10 mins, until everything has come together and you have a very soft and stretchy dough. Add a light sprinkling of flour to the surface and your hands as you go to stop the mixture sticking, but try not to add too much. Place in a lightly greased bowl and cover with cling film. Leave in a warm place for 2 hrs until doubled in size.
Place the raisins and sultanas in a small saucepan with the rum and heat gently for 5 – 7 mins until the fruit has absorbed the liquid and is plump and juicy. 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, sultanas and chopped candied peel. Shape the dough into a ball and pop into the prepared tin. If using a 20cm cake tin, wrap a layer of baking parchment around the outside of the tin, to come up about 5cm above the rim, and secure the paper with string. This will help contain the dough as it rises. Cover lightly with cling film and leave to rise for another hour until it has risen to the top of the tin or paper.
Preheat the oven to 350 F.
Mix the remaining egg with the 3 tablespoons of milk and brush over the surface of the cake. Cook in the middle of the oven for 20 minutes. Lower the heat to 300 F and cook for a further 40 minutes. The panettone is ready when a skewer comes out clean.
Let the cake cool for 5 minutes in the tin on a cooling rack, then remove and leave it to cool completely.
Serve and enjoy!