I remember looking this recipe up on the internet in around 1998 and I had to do exhaustive searching to find a single recipe. Now there are tons, as well as several videos of how to make it. Pão de Queijo are just as easy to make as buttermilk biscuits, but are arguably more delicious. They are springy little puffs of tapioca starch and cheese and go well with virtually anything--what's more, they only take about 35 minutes to make from start to finish. The only hard part is keeping tapioca starch (aka tapioca flour, manioc flour, cassava flour) on hand, though this is easy to find at any Asian store and is usually cheap. You also need a hard, mild cheese that won't overwhelm the puffs. I used a combination of parmesan and white cheddar.
2 c. tapioca starch
1 c. milk
1 c. water
1/2 c. vegetable oil
1 tsp. salt
~1 c. grated hard, mild cheese
Preheat the oven to 450.
Place the tapioca starch in a large bowl. Bring the milk, water, vegetable oil, and salt to a boil. Pour it slowly over the starch while stirring with a wooden spoon, making sure to moisten completely. Keep stirring until it is just cool enough to handle. Crack the eggs into the bowl and squish them in as thoroughly as possible, using your hands. It will look like a mess at this point and the dough will remain very sticky. Still using your hands, mix in the grated cheese until it is evenly distributed.
Cover 2 cookie sheets with parchment paper. Oil your hands and lightly roll the dough into golf-ball sized rounds and place these on the sheets. Bake at 450 for 10 minutes, then reduce the heat to 400 and cook 10 minutes more until puffed and browned. Serve piping hot.
This recipe can be increased or decreased. As-is, it will make about 3 dozen puffs.
Apparently these are best made with 'polviho azedo', sour manioc flour, or a combination of it and regular tapioca flour. If you can find this stuff, then your pães will be more puffy and have a slightly sour flavor, or so the internet tells me. Let me know if you find it and try it out.
The leftover pães heat up well in the microwave (~30 sec.) and are surprisingly good with jam.