Preheat your oven to 425°F, and grease or line muffin tray with liners
Weigh or measure out your walnuts and chop finely. If you like nuts you can chop them a bit more roughly, I chopped most of mine to about ⅓ the size of a grain of rice.
In a medium bowl, weigh or measure out your flour, add in salt, sugars, baking powder, cinnamon and chopped walnuts. Mix until combined.
In another medium bowl, add melted butter, oil, eggs, milk. Zest orange into liquid mix and whisk together until combined.
Pour flour mix into liquids and mix until just combined. Do not overmix.
Add in blueberries and gently fold into batter.
Add batter into prepped muffin tin, filling each about 3/4 of the way full.
Generously sprinkle turbinado or demerara sugar on the muffin tops.
Lower oven temperature to 350°F as muffins go into the oven. Bake muffins for 22-25 minutes on center rack. A toothpick inserted will come out cleanly.
Remove muffins from tins and onto a cooling rack. Enjoy while warm!Muffins will keep in an airtight container for a few days.