Warm the milk until lukewarm. Dissolve the yeast in half of the milk, then add the sugar to this mix. Leave the yeast mix to rest in a warm spot for a short while. Peel the apple and cut into cubes.
Meanwhile, sieve the flour and salt into a big bowl. Make a small dip in the flour, then pour the yeast mix into it. Starting from the middle, and using a blender, mix the batter until smooth and clump-free.
Whisk the egg and the remaining milk into the batter. Then add the raisins, currants, apple cubes, and candied lemon peel to the batter. Cover the batter with plastic cling foil, and leave to rest in a warm place for at least 30 minutes.
Heat the oil in a deep frying pan (to 180C). With two oiled spoons, scoop a portion of batter and carefully slide it into the oil. Fry the beignets for about 6 minutes until golden. Place them on a paper kitchen towel and leave to drip. This recipe will make for approx. 25 beignets.