In a large bowl, stir together chopped orange, orange juice, dates and sugar. In a separate bowl, mix together flour, baking powder, bicarbonate of soda and salt. Stir flour mixture into orange mixture just until combined. Do not over mix. Fold in soured cream. Spoon batter into prepared muffin tin.
Bake in preheated oven for 15 to 20 minutes, until a small knife inserted into centre of a muffin comes out clean. Remove from tin and let cool before serving.