For buttermilk pancakes, combine flour, icing sugar and orange rind in a bowl. Place egg yolks and buttermilk in a jug and whisk lightly to combine, then pour into flour mixture and whisk to combine. In a separate bowl, whisk eggwhites until soft peaks form, then fold through flour mixture and set aside.
Halve nectarines and cut each half into 3 wedges. Combine ½ cup sugar, orange juice and Grand Marnier in a large frying pan and stir over medium-high heat until sugar dissolves. Bring to the boil and cook for 1-2 minutes or until syrupy, add nectarines and cook for 1-2 minutes on each side or until nectarines are glazed and just soft. Remove nectarines from pan, add 2 tbsp water and stir to combine, then set aside.
Heat half the vegetable oil and butter in a separate frying pan over medium heat. Add ¼ cupfuls of pancake mixture and cook in batches for 2-3 minutes on each side or until golden. Repeat with remaining oil, butter and mixture.
Combine remaining sugar and orange rind in a small bowl. Serve pancakes with glazed nectarines, drizzle with pan juices, scatter with orange sugar and dust with icing sugar. Serve with ice-cream or crème fraîche if desired.