Preheat oven to 350 degrees. Line 14 cups of
two 12-cup muffin tins with baking cups,
and lightly coat each with cooking spray.
Whisk together flours, sugar, baking
powder, and 1/2 teaspoon salt in a large bowl. Whisk together
yogurt, oil, eggs, and egg whites in a
medium bowl. Fold yogurt mixture into flour mixture, then gently fold in parsnip
and rosemary until combined.
Spoon batter into baking cups until
each is three-quarters full. Sprinkle each muffin with
a pinch of coarse salt. Bake until a
toothpick inserted into the center of each
comes out clean, about 25 minutes.
Transfer pans to wire racks, and let cool
for 10 minutes. Turn out muffins
onto racks, and let cool completely.