Using a medium to a large-sized saucepan, combine 3 1/2 cups of water with salt and mix.
Add the rice and lemon rind, cover with a lid and bring to a boil.
Simmer until rice is cooked. This generally takes 20 minutes.
Add the 3 & 1/2 cups of hot milk and the vanilla pod.
Mix to combine, then cover and continue simmering until the liquid has reduced and the rice turns soft and creamy (about 20 to 30 minutes). Stir regularly the entire time.
Add sugar and mix. Cover with a lid and bring to a boil.
Temper egg yolks with the remaining milk (not hot!) and beat with a fork.
Remove the sweet rice from the heat and take the rind and the vanilla bean out.
Add the tempered yolks slowly while stirring constantly.
Bring the saucepan back on the heat, cover with a lid, and bring to a boil.
Taste and adjust seasoning, as desired.
Remove from the heat and transfer to serving bowls.
Decorate the top with cinnamon powder.