Line a 12-section muffin tray with paper muffin cases. Put the flour, baking powder and sugar in a bowl and stir together using a fork.
Melt the butter in a small saucepan over a gentle heat and then pour into the dry ingredients. Add the eggs, oil, vanilla extract and yogurt and stir together until only just combined. Stir in the fresh berries. Divide the muffin mixture between the paper cases.
Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 15 minutes or until the muffins are well risen and the tops have cracked and turned golden brown.
Loosen the edges of the paper cases with a round-bladed knife to serve warm or transfer to a wire rack to cool.