Preheat oven to 170C fanforced (190C conventional).
Line a 12 hole muffin tin with paper cases.
Mix flour with sugar, baking powder and salt in a large bowl and set aside.
In another bowl, stir in cheese, yoghurt, butter and eggs.
Gently stir into flour mix until just combined. The mixture will be thick and slightly lumpy. Do not over mix or your muffins will be tough.
Place in 12 muffin cases. Bake in oven for 20 -25 minutes, until a skewer inserted comes out clean.
Remove from oven and cool on wire racks.