Place the buttered bottom half of your Hot Cross Buns into a lightly greased 11x7 inch pan. Sprinkle the raisins/sultanas/currant all over the bun bottoms. Place the tops of the buns on top of the raisins.
*You may need to cut one or two buns in half from top to bottom to make sure they all fit in the pan snuggly and in rows.
Place milk and cream into a medium sized saucepan over a low heat. Bring to a simmer, stirring frequently. Be careful not to boil the mixture, when it bubbles around the edges, it's done!
Place eggs, sugar and vanilla extract into a medium sized bowl and whisk together until smooth.
Once the milk mixture is done, pour a small amount into the eggs and whisk. Continue pouring the hot mixture into the eggs very gradually, whisking as you go. If you add the hot mixture too quickly, you'll scramble the eggs.
Once all the milk is combined with the eggs and you have a smooth mixture, slowly pour the mixture all over the Hot Cross Buns.
Leave the pan for 30-40 minutes for the Hot Cross Buns to absorb some of the mixture. At this stage you can cover and place in the fridge overnight if desired.
After 30 minutes, preheat the oven to 160C/325F and place the buns into the oven for 35-40 minutes, until golden and crisp on top and if you shake the pan gently the middle is set. You can also insert a skewer and if it comes out clean, then it's done.
Leave to cool for at least 30 minutes before serving. Serve warm or cold, with custard or cream. Hot Cross Bun Pudding will keep covered, in the fridge, for 5 days.