Preheat the oven to 400°F.
Spray a 12-cup muffin tin with nonstick spray or fill with paper liners.
Combine the flour, sugar, baking powder, baking soda, & salt in a large bowl.
Use a pastry cutter or cross 2 butter knives to cut in the butter until the mixture is crumbly.
Whisk in the milk, yogurt & egg, in a separate large bowl.
Pour the milk mixture into the flour mixture & whisk just until blended.
Gently fold in the blueberries.
Spoon the batter into the prepared muffin cups, filling each about two-thirds full.
Bake until the muffins are golden brown or the toothpick test comes out clean, approx 20 minutes.
Cool the muffins in the pan on a wire rack for 10 minutes.
Remove the muffins from the pan & cool completely.