In a bowl beat the egg with yogurt, rum and grated lemon peel. Add powdered sugar and salt, sift the flour and baking powder and fold into the egg mixture gently. Combine to a smooth dough that feels fluffy. Leave dough to rest for 30 minutes.
In a large frying pan heat oil. You need to fry in a large quantity of oil, as the fritters need to float. If you want to test when the oil is hot enough, just put in a small chunk of dough. If it sinks, it's not hot enough yet, if it floats and generates bubbles, you're ready to fry.
Use a spoon to form the fritters. Just spoon some dough out of the bowl and place it into the hot oil. If the dough does not slide down, just use another spoon and scrape it off. The fritters will usually turn around in oil by themselves, but if they do not, just turn them when they are golden brown and fry on the other side. When done, remove the fritters out of the oil and place them on a paper towel to cool and dry the excess oil.
Repeat process until you run out of dough.
Sprinkle the fritters with powdered sugar while still warm and serve.