Combine the saffron strands with the olive oil in a small mixing bowl. Whisk a few times then set to one side for 5 minutes.
Melt the butter in a frying pan set over a medium heat and sweat the shallot for 5 minutes, stirring frequently. Increase the heat and add the infused oil to the pan. Sauté the prawns for 3-4 minutes until pink and tender.
Remove from the heat and season to taste with salt, pepper and lemon juice.
Finish with the single cream, stirring well. Spoon into serving bowls and garnish with the chives before serving.