Sift the flour, baking powder, baking soda, cinnamon and salt together in a large bowl.
Stir in the sugar.
Whisk the yogurt, eggs and oil together in a smaller bowl.
Add the yogurt mixture to the dry ingredients all at once.
Stir together until just combined. Do not beat.
Divide the mixture between twelve muffin cups.
Sprinkle with the streusel mixture. Divide it evenly between the yogurt muffins.
Bake for 15 to 20 minutes or until a skewer inserted in the centre of a muffin comes out clean.
Serve warm.
Cinnamon Streusel Yogurt Muffins will keep in a sealed container for up to 3 days.