Preheat oven to 220°C / 425°F. Line a 12-cup muffin tray with paper liners.
In a large bowl, whisk together eggs, caster sugar, melted butter, milk, and yoghurt until smooth.
Sift in flour, baking powder, bicarb soda, and salt. Gently fold until just combined.
Add raspberries and chocolate chips. Fold carefully to avoid overmixing.
Divide the batter evenly between the muffin liners, filling each almost to the top. Sprinkle with raw sugar for a golden, crunchy top (optional).
Bake for 5 minutes at 220°C / 425°F, then reduce oven temperature to 180°C / 350°F and continue baking for 15–18 minutes, until muffins are golden and cooked through.
Cool slightly on a wire rack, then dust with icing sugar and drizzle with melted chocolate before serving.