Apple. Cinnamon. Doughnut. What’s not to love?!
To make batter; whisk flour, baking powder and 1 teaspoon of the cinnamon in a bowl. Set aside. In a separate bowl, whisk together buttermilk and eggs until well combined. Add to flour mixture and whisk until smooth.
Heat a large saucepan over a medium heat and pour in enough oil to come halfway up the sides. Heat until a piece of bread sizzles and turns golden (about 175°C, see tip). Cut one apple at a time into 8mm-thick slices. Using a 3cm round cutter, cut out the core. Put apple rings in batter and turn to coat.
Using a fork, lift an apple ring out of batter, allowing a little to drip off. Lower into hot oil. Cook 3 rings at a time for 3-4 minutes, turning until puffed and golden.
Combine sugar and remaining cinnamon in a large bowl. Add hot apple rings and turn to coat lightly. Repeat with remaining apples and batter. Serve immediately, drizzled with maple syrup.