Preheat oven to 350 degrees and place oven rack in center position
To prevent the cake from sticking you can use non stick pans, if your pans are not non stick use paper towel to wipe sides and bottom of pans with soft butter. Dust each pan lightly with flour.
Combine flour, baking powder and salt, set aside
Place butter, coconut oil, sugar and vanilla in mixer and mix until well combined
Add eggs one at a time
Alternate adding flour mixture with buttermilk until well combined, mix for one more minute
Add orange zest and mix until incorporated
Add blueberries and gently mix in by hand
Pour equal amounts of batter into prepared pans, tap pans firmly on counter to take out any bubbles
Bake for 25-30 minutes or until an inserted toothpick comes out clean
Allow cakes to cool, gently remove from pans, then frost