Once the Cream Puffs are cooled down, remove from the oven and then preheat the oven to 180 C (160 C fan Forced or 350 F)
Roast the macadamias and almonds for 8-10 minutes, keeping a clode eye on them to ensure they don't get too dark.
In a saucepan, mix together the sugar and water and heat gently until sugar is melted and has turned a golden brown. Do not stir. However, you can swish the saucepan occasionally.
Add the nuts to the sugar mixture and then quickly stir and pour the praline mixture out onto the baking tray, spreading it out quickly before it starts to set. Leave to cool down while you make the custard.
Whisk together the egg yolks and sugar until light and creamy. Add the cornflour and mix well
Heat the milk and vanilla in a medium saucepan until small bubbles start to form around the edges of the saucepan.
Gradually add a little of the hot milk to the egg mixture, whisking as you go to ensure that the eggs don't scramble. Continue to add the hot milk a little at a time, whisking well all the time until all the milk is incorporated into the egg mixture.
Pour the mixture back into the saucepan and heat until custard comes to the boil thickens. Continue to heat and whisk for a few more minutes. Remove from the heat.
Cover the custard with plastic wrap, pressing the wrap onto the surface of the custard so there is no air between the plastic wrap and the custard so that no skin forms. Place the custard in the fridge to cool down
Once the custard is cool, break up the praline and reserve some of the caramelised nuts for the tops of the cream puffs. Place the rest of the praline into a high speed blender (I used a Nutri Bullet) and blend until it is liquefied and smooth with no lumps
Once the custard is cool, mix about 3/4 of the praline mixture into the custard mixture and taste test. Add more of the praline mixture to taste.
Put this mixture into a piping bag fitted with a smaller nozzle (I used a Wilton 1A) and refrigerate until ready to use