Chocolate Spelt Muffins (with White Chocolate Chunks)

Name: Chocolate Spelt Muffins (with White Chocolate Chunks)
Prep time: 10 min
Cook time: 25 min
Total time: 35 min
Cuisine: American
Ingredients: 115g (½ cup) butter (melted); 170g (¾ cups) sugar; 2 eggs; 3 tbs strong brewed coffee (cold); 1 tsp vanilla extract; 180g (1½ cups) spelt flour (see note 2); 35g (⅓ cup) cocoa powder; ¾ tsp baking soda; 1 tsp baking powder; 100ml (⅜ cup) Greek yoghurt; 150ml (⅔ cup) milk; 100g (3½ oz) white chocolate