Preheat your oven to 400°F (200°C).
Add tapioca flour and salt to a large bowl and mix.
In a saucepan, combine the oil and milk. Heat the mixture over medium heat for about 5 minutes, until it starts to boil. Turn off the heat.
Carefully pour the hot mixture over the tapioca flour mixture.
Stir with a spoon and let it cool until you can handle it with your hands.
While the mixture cools, grate the cheeses using the coarser side of a grater:
Once the mixture has cooled, add one whole egg and start mixing. One hand holds the bowl while the other brings the dry tapioca to the center. Then, press the dough well to mix all the ingredients.
Check the consistency of the dough. It should be a little sticky. If it isn't add 10g (1tbsp) more milk to make the dough a bit stickier. Press with your fingers to help absorption and keep pressing and folding the dough until it returns to a uniform consistency (about 5 minutes).
Add the grated cheeses to the dough and press again just until the cheese is well mixed.
Divide the dough into portions of about 60-70g each. I recommend weighing the entire dough and dividing by 12 for consistent sizing.
Weigh a portion of dough and roll it with both hands to form a ball. Use oil on your hands if the dough is sticky and spread it over the entire surface of the dough balls. This also prevents sticking to the baking sheet and helps to brown the crust.
Place the balls on a baking sheet lined with parchment paper, leaving about 4 centimeters of space between them.
Bake in the preheated oven for 30 minutes
If the row at the back starts to brown while the front row is still pale, rotate the baking sheet and bake for another 5 minutes.
Serve and enjoy your Pão de Queijo fresh and warm out of the oven!