In a medium bowl, whisk flour, baking powder, salt and orange zest together until combined
In a large bowl, beat butter and granulated sugar together until light and fluffy.
Add eggs, orange juice and vanilla extract. Beat until combined. .
Alternating flour mixture and buttermilk, add about half the flour mixture, mix just until combined then add half the buttermilk and mix just until combined. Repeat flour and buttermilk just until combined.
Pour batter into the prepared loaf pan.
Bake for 45-50 minutes or until a toothpick inserted in the center comes out mostly clean.
Remove from the oven and let sit in the pan for 5 minutes then transfer to a wire rack to cool.