4 tablespoons cold-pressed, fruity olive oil (for example the Picual variety)
Mint leaves, to garnish
Carefully peel the oranges, being careful to remove the pith completely. Cut the oranges into thin segments and arrange in a dish or on dessert plates. Place the olives on top. Mix the orange and grapefruit juice together and pour over the oranges. Leave to marinate. Before serving drizzle olive oil over and garnish with mint leaves.