Slice off the top and bottom of the oranges, then peel all round the fruit down to the flesh. Using a sharp knife, cut out the segments between the white membranes, retain the juice (approx. 50 ml), set aside.
Boil the sugar and 2 tbsp water in a wide-bottomed pan without stirring. Reduce the heat and simmer, swirling the pan occasionally, until the sugar darkens to a hazelnut-brown caramel. Stir the nuts into the caramel, spread onto a sheet of baking paper, leave to cool.
Combine the reserved orange juice and rapeseed oil, season. Arrange the beetroot on plates so that they overlap slightly, mix the endive leaves with half of the dressing and place alongside. Arrange the orange and nuts on top, drizzle with the remaining dressing.