In a large bowl, combine the yeast with warm water, and 1 teaspoon of sugar, until dissolved. Leave the mix to stand for 4-5 minutes for the yeast to activate and begin to form bubbles.
Prepare the dough by adding the sugar, eggs, vanilla, milk, melted butter, 1 teaspoon of salt, and the the flour to the yeast mixture. Combine everything a and knead the dough either using a dough hook or your hands adding more warm water or flour as necessary until it becomes firm and elastic (about 8 minutes).
When done, cover the bowl with a clean cloth, place it in a warm location and allow the dough to leaven for 45 minutes or until doubled in size.
Next, take a medium-sized pot and fill it with about 2 inches (5 cm) of oil. Heat to 350 °F/ 176 °C.
While the oil is heating up, transfer the risen dough onto a clean, lightly floured surface and divide it into 8 pieces.
Take each dough piece and shape it into a ball by pulling the outer edges toward the bottom center of the dough ball. Let these dough balls rest, covered, for 15 minutes.
In a bowl, combine 2 cups (400 g) of sugar with 2 tablespoons of cinnamon, mixing them together until even.
Check the oil’s temperature by tearing off a small piece of dough and see if it sizzles and floats to the surface.
Once the dough has rested and the oil has reached the desired temperature, use a rolling pin to flatten the dough balls into oblong shapes, similar to a beaver's tail. These should be very thin, approximately ¼ inch thick or less.
One at a time, gently place the flattened dough into the hot oil. Fry each piece for about 30 to 60 seconds on each side, using tongs or chopsticks to flip the dough.
Once fried, remove the beaver tail from the oil and allow any excess oil to drip off for a moment before dipping it into the cinnamon and sugar mixture. Ensure it is fully coated on both sides.
You can customise them however you like by drizzling chocolate or caramel sauce on top and adding fruit like banana or strawberry slices. Serve warm and enjoy!