Start by making the creme patissiere. Pour the milk into a pan and bring to the boil. Take it off the heat.
Whisk egg yolks with caster sugar until mixture is thick and creamy. Slowly pour the milk into the mixture stirring constantly. Return to heat and bring to the boil slowly. Stirring constantly. It should take about 3 minutes and the mixture will have thickened.
Pour the mixture into a bowl and cover with cling film. Let it cool for at least an hour.
Make the almond cream: Whisk egg yolks with caster sugar until the mixture is thick and creamy. Add the almond powder, butter and rum.
Once the creme patissiere has cooled, whisk until it is smooth and then combine it with the almond cream. Voila: frangipane. This quantity is enough to make 2 galettes.
Place one of the puff pastries on floured surface. Trim to make a 24cm disk. Egg wash the edges and prick the pastry. Place half the frangipane in the centre of the disk and spread to edge of egg wash.
Trim the second puff pastry to make a second disk slightly larger than the first. Then carefully place on top of the first disk.
Seal the edges. Egg wash the top and place in fridge for 30 minutes.
Preheat oven to 190 degrees Celcius. Take galette out of fridge and brush egg wash all over. Place in the oven and bake for 40 minutes or until golden.