Preheat oven to 375. Line a muffin tin with muffin cups and spray with cooking spray.
In a medium bowl, combine almond flour, whole wheat flour, brown sugar, flax seed, baking powder and salt.
In a medium bowl, whisk together thawed raspberries (with their juice), milk, almond butter, egg and vanilla until almond butter is incorporated smoothly into mixture. Lightly mash the raspberries as you mix.
Add wet ingredients to dry ingredients and stir until combined.
Spoon batter into muffin tins, filling each tin about 3/4 of the way up. Batter should fill 12 muffin tins.
Bake muffins for 22-25 minutes or until lightly golden brown and a toothpick inserted comes out clean.