Preheat the oven to 350 degrees F and prepare muffin tin with paper liners or use silicone muffin cups.
Add dry ingredients to a large bowl and mix to combine.
Add wet ingredients to a medium bowl and whisk until combined.
Transfer the wet ingredients to the dry ingredients and stir to combine. Don’t overmix.
Fold in the blueberries and walnuts, if using.
Fill muffin tins ¾ of the way full.
Bake for 20 minutes or until golden brown on top.
