Cream butter and sugar together. Beat in eggs one at a time.
Mix flour and baking powder together. (I just do this in the measuring cup to avoid another bowl to wash.)
Alternate adding dry ingredients then liquid ingredients to the sugar mixture until well blended. Pour batter into two greased loaf pans and bake at 350F for 45-50 minutes.
Let hot loaf pans sit for 10-15 minutes, then remove to a wire rack for cooling.
Notes
I've successfully used oat flour for this recipe, too, but it's a bit more crumbly.This recipe calls for passion fruit juice. If you have access to fresh passion fruit, follow these instructions for how to juice passion fruit.If you really want to use passion fruit juice for this recipe but the fruit is not available locally, I'm told that ethnic grocers often carry a liliko‘i puree in their freezer section.