Preheat oven to 220°C. Lightly coat a baking tray with non-stick cooking spray. Drain fresh tomato on paper towels.
Combine flour, baking powder and salt in a medium bowl. Combine yogurt and oil in a small bowl; stir into flour mixture just until evenly moistened.
Stir fresh tomato, spring onion and sun-dried tomato into flour mixture. Drop dough, ¼ cup at a time, onto the prepared baking tray, making 12 scones.
Bake until the tops are golden brown, about 12 minutes. Serve warm or at room temperature.
Baking powder, vegetable oil and yoghurt are the ingredients that produce a soft, flaky scone. To make the tops browner, brush the scones with milk or oil before baking. To add more flavour, include 2 tablespoons of finely chopped ham, chives or mild chillies in the batter. Scones freeze well so it's well worth making a double batch and storing some for later.