Generously grease & flour a 10” bundt pan or 12 mini loaf pans.
Using an electric mixer, cream butter, lilikoi butter, & sugar together until fluffy. Add eggs one at a time, beating well after each egg. Sift together flour, baking powder, & salt. Alternately add flour mixture & heavy whipping cream to the butter-sugar mixture, beginning & ending with flour. Stir in passion fruit juice.
Pour batter into prepared pan(s). Place in a cold oven, set oven temp. to 325 degrees F & bake for 1 hour & 15 minutes (bake 45 minutes for the mini loaves) without opening the oven door. Bake for an additional 15 minutes if cake is not done. Remove from the oven & cool in the pan(s) for 15 minutes. Invert cake(s) onto cake plate(s).