Grease and line a loaf tin so that the paper extends over the long sides to make handles.
In the bowl of an electric mixer, beat the butter and sugars together until light and creamy.
Add a the eggs and mix until just combined.
Take the bowl off the stand and sift in the flour and bicarb then stir them through until there are no dry bits.
Add the passionfruit and mashed bananas to the bowl and stir them in until just combined.
Spread the batter into the tin and smooth out the top.
Halve the passion fruit and scoop out the pulp into a sieve over a bowl.
Bake the cake for 55 minutes or until a cake tester inserted in the middle comes out clean.
Leave the cake to cool completely in the tin.
Notes
Tip: If you don't like passionfruit seeds, you can strain the pulp and just use the juice in the batter. Serve: It's most delicious served as a thick slice toasted & spread with butter.