Peel the oranges, taking care to remove as much of the white pithy rind as possible. Slice the peeled oranges horizontally into slices 0.5cm thick.
Slice the halloumi into 0,5cm thick slices and pat each slice dry on some paper towels.
In a non-stick pan over medium heat, dry-fry the shelled pistachios, turning frequently to prevent catching, until they start to brown. Remove from pan and allow to cool.
Wipe out the pan and over medium heat, melt the butter and add the sugar until it starts to bubble, then lay the orange slices in the pan in a single layer (depending on the size of your pan you may have to do this a couple of times to fit all the slices in). Fry until the orange slices start to caramelise, then turn over and repeat on the other side.
In a second non-stick pan, heat the olive oil over medium heat. Lay the halloumi slices in a single layer in the pan and fry until golden, then turn them over and repeat on the other side. When golden brown on both sides, remove from the pan and drain on paper towels.
Arrange the salad leaves in a serving bowl or platter, then lay the caramelised orange slices and the halloumi slices on top. Sprinkle the lightly crumbled toasted pistachios over the top.
Dress with dressing of your choice (I make a mixture of olive oil, orange juice, salt and pepper) and serve immediately.