Preheat the oven to 180°C and fill a pan with paper liners for 12-14 cupcakes.
In a bowl, sift the flour and baking powder. Mix well, and then add the green olives, chopped onions, mint, and salt. Stir well.
Place the eggs in the bowl of a mixer and beat until fluffy. Reduce the mixer speed and pour in the milk and olive oil. Spoon by spoon add half of the flour mixture, followed by the orange juice, and then the remaining flour mixture. Fill the paper liners with the cupcake batter until they are about 2/3 full. Bake in the preheated oven for 25 minutes.