Beat together the eggs and sugar. Blend in sour cream, vanilla and rum or brandy. Fold in sifted flour and salt. Knead dough on floured surface until the dough is smooth.
Cut off a small portion of dough and roll out as thin as possible (almost paper thin). The dough will spring back as you roll it if you treat it like a pie crust.
Cut into 5cm wide strips. Cut the strips diagonally every 10cm. In the middle of each biscuit cut a 3cm slit. Pull one of the pointier corners through the slit. If you are making these alone, it is suggested that you do all of the rolling and cutting before frying, or in two batches. If two people are making the biscuits, the roller/cutter should get a "stockpile" before frying begins.
Heat oil to hot (180 degrees C). An electric frypan works well, especially if you are working alone. Slide about seven or eight biscuits into the oil. They should pop up to the top of the oil after a second.
Very soon, the biscuits should be a light brown (or very dark tan) on the bottom. Flip the biscuits; a two-tined carving fork works well. When the second side is browned, remove from the oil with a slotted spoon and drain on paper towels. When the paper towel is filled with biscuits, shake icing sugar over the biscuits and move the biscuits, paper towels and all, to a baking tray.