Heat oven to 350°F. Coat a standard 12-indentation muffin pan with nonstick cooking spray. On waxed paper, sift together the flour, sugar, baking soda and salt.
In a large bowl, whisk together the yogurt, 1/4 cup water, the egg, egg white and melted butter. Stir the flour mixture into the yogurt mixture just until moistened. Gently fold in blueberries.
Divide batter evenly among the prepared muffin indentations, about a heaping 1/4 cup batter for each. Sprinkle crushed granola over all muffin tops (dividing evenly).
Bake muffins at 350°F for 20 minutes or until crowned and golden around the edges. Let muffins cool in the pan on a wire rack for 5 minutes. Transfer muffins directly to rack; serve slightly warm, if desired.