Preheat oven to 375°.
Whisk together the flour and next 5 ingredients (through salt) in a medium bowl.
Whisk together yogurt, oil, lemon rind, and eggs. Pour into the flour mixture, stirring until just blended. Spoon the batter into 12 muffin cups coated with cooking spray. Sprinkle evenly with raspberries and 1/2 teaspoon of sugar.
Bake 20 minutes or until muffins spring back when touched lightly in the center. Remove from the oven and cool 5 minutes in the pan. Remove muffins from the pan and transfer to a wire rack to cool.