1canola oil, for frying cinnamon-sugar, for dipping (spike sugar with as much cinnamon as you like)
2In a large bowl, stir together the yeast and water; set it aside for 5 minutes, until it’s foamy. (If it doesn’t foam, throw it out and buy fresh yeast. It won’t foam much, but if it just sits there and does nothing, it’s inactive.) Add the flour, milk, butter, egg, sugar and salt, and stir until you have a soft, sticky dough. Stir for a minute or two, then cover and set aside for an hour, if you have time and aren't at a 10th birthday party.
3Turn the dough out onto a lightly floured surface and pat with floured hands until it’s about 1/2 inch thick. Cut out as many rounds as possible with the rim of a shot glass, and poke a hole in each with your finger, stretching it out a bit as it will puff up as it cooks, closing the hole somewhat. If you like, cover with a kitchen towel and let them rise for another 20-30 minutes (this isn’t necessary, but will produce lighter doughnuts).
4Heat about 2” of oil in a deep, heavy saucepan until it’s hot but not smoking. You’ll know when it’s hot enough by dipping in a piece of bread or a bit of dough – it should start sizzling right away. If the oil is too cool, they will take too long to cook and will absorb too much oil, making them heavy.
5Cook doughnuts 2 at a time, turning occasionally with tongs or a slotted spoon, until puffed and golden brown, about 2 minutes per batch.
6 Transfer to paper towels to drain, then toss in cinnamon-sugar while still warm.