Heat oven to 375ºF. Coat a standard 12-cup muffin pan and one small oven-safe ramekin with nonstick spray.
Whisk together the flour, baking powder, baking soda, and salt in a large mixing bowl. In a second bowl, whisk together the sugar, oil, eggs, egg yolks, yogurt, and orange zest until smooth.
Make a crater in the middle of the dry ingredients and pour in the wet ingredients. Stir with a rubber spatula until just barely combined. Resist the urge to overmix — there should be some lumps of flour in the batter.
Fold in the blueberries, mixing just to combine.
Drop about 1 cup of batter in each of the muffin tin's wells. Whatever's leftover can be dropped into the prepared ramekin. The cups should be quite full.
Sprinkle the muffins with the demerera sugar and bake or until a toothpick inserted into the bottom of a muffin comes out clean, 25 to 30 minutes.
Remove from oven and turn out, upside down, onto a clean tea towel to cool completely. This step is key in preventing mushy muffin bottoms, which nobody, and I do mean nobody, likes.
Serve immediately or store in an airtight container for up to 1 week.