Preheat the oil in a deep fryer to 375°F (190°C). Line a baking sheet with paper towels.
In a bowl, whisk together the flour, baking soda and baking powder.
In a large bowl, beat the eggs and sugar with an electric mixer until the mixture triples in volume and forms a ribbon as it falls from the beaters. Fold in the dry ingredients using a whisk, then stir in the apples.
Spoon the mixture into a pastry bag fitted with a 1/2-inch (1 cm) plain tip.
Pipe the batter in a spiral motion into the hot oil to create 4-inch (10 cm) funnel cakes. Watch out for splattering. Fry for 2 to 2 1/2 minutes, flipping halfway through cooking. Drain on the paper towels and let cool.
In a small bowl, combine the icing sugar and cinnamon. Using a fine-mesh strainer, sift the mixture onto the funnel cakes.
Delicious served with baked apple sorbet (see recipe below) or vanilla ice cream.