Preheat oven to 350 degrees and grease muffin pans.
In a large bowl sift the flour with baking powder & salt and set aside. Remove one tablespoon of this mixture which will be tossed with the blueberries.
In another bowl, whisk the sugar, oil, egg and yogurt. Add the wet indregients to the dry and mix until just blended. It will be lumpy but if you overmix the muffins will be tough. [Count about 11 mixes and stop]. Add the coated blueberries to the mixture and gently stir 3 more times. The batter should be somewhat thick.
Using a large ice cream scoop [#20 or 4 oz cup size] scoop mixture into each muffin pan. Sprinke with cinnamon sugar and bake for about 20-25 minutes, until tops are nice & brown. Let muffins cool at least 15 minutes before removing them from the pan.