Yes, the feijoada was incredible, but perhaps the very best thing I ate while in Brazil a couple weeks ago was the first thing I had after touching down. Pão de queijo, Portuguese for "cheese bread," are tiny cheese puffs made with yuca (not to be confused with yucca) flour and a slightly sour, tangy fresh cheese. They smell awesome when they're hot.
Yuca (also known as cassava or manioc) is a starchy root vegetable that's a staple carb for many South and Central American diets. It's great fried, steamed, or mashed, but it's at its best when dried and milled into tapioca flour. It turns pleasantly stretchy and gooey when baked, but unlike other starches, will never get doughy or gummy.
Check out that stretch!
They tend to get stale pretty fast, so the best way to eat them is hot, fresh out of the oven, when the outer shell is still thin and crackly. I like to pull them in half so the inside bursts open with a puff of cheese-scented steam. This method also lets you admire its stretch before deciding which is the better half to bite into.
There's a dearth of great Brazilian bakeries in my neighborhood, which leaves two options: make them myself, or buy them frozen. The latter is remarkably easy, and actually gives you really fantastic results. Frozen pão de quiejo comes raw and pre-shaped. You can bake them straight from the freezer, which means hot, cheesy bread is only a preheat and 25 minutes away.
Look for a good Brazilian or Latin grocer. If you live in NYC, you can get them out in Queens or at Buzios, on 46th between 5th and 6th (they're sold as "cheese puffs").
My Colombian wife may be upset when she reads this, but I think I may actually prefer pão de quiejo to the very similar pan de yuca, which seem to differ really only in shape. (Luckily my wife is out of the country for the next couple months, and will hopefully forget reading about this infraction before she gets back.)