Preheat your oven to 350°F (175°C).
Line a muffin tin with parchment paper or muffin liners.
In a large mixing bowl, whisk together the whole wheat pastry flour, baking soda, salt, and raw sugar.
In another bowl, combine the unsweetened applesauce, beaten egg, melted butter, and vanilla extract. Whisk until smooth.
Pour the wet ingredients into the dry ingredients and gently fold until just combined.
Gently fold in the blueberries.
Scoop the batter into the prepared muffin tin, filling each cup about 2/3 full.
Bake for 18-20 minutes or until a toothpick comes out clean.
Cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.