Whisk flour, sugar, baking powder, salt, and baking soda in large bowl to blend.
Rub chilled butter between fingertips into dry ingredients until mixture resembles coarse meal. Add yogurt mixture and stir with a wooden spoon until the mixture is evenly moist and begins to form a ball of dough. Add 1 tablespoon of milk if too dry.
Using a cup dry measure, scoop dough, and drop onto baking sheet, spacing 2 inches apart. Bake until golden brown, about 15 minutes. Transfer to a rack to cool.
If you cannot find whole wheat pastry flour then substitute half whole wheat flour and half all-purpose flour. Just swapping in whole wheat flour will result in a drier and grittier biscuit.
Eat all sweet, sugary treats in moderation. A little bit of what you like does you good, but don’t overdo it!