To make the cakes: Peel and chop the potatoes into bite size chunks. Bring them to the boil in a pot of salted water. When they are tender, strain them off. Tip them back into the pan and place them over a low heat – this is to ensure most of the moisture has evaporated away. Mash them roughly with a masher and set them aside to cool while you make the tartar sauce.
Tip the mayonnaise into a bowl. Finely chop the gherkins and capers. Add these to the mayonnaise along with the dill, mustard and lemon. Set this aside in the fridge until the cakes are ready.
Open the banana blossom, strain off the water and roughly chop them – not too finely though, as they are going to lend the main texture to the finished cakes.
When the potatoes have cooled, tip in the chopped banana flowers, the soaked wakame, the kelp, mustard, lemon zest and chives. Season the mixture to taste.
Take two large dinner plates and coat the first one in panko bread crumbs. Take about 1/8th of the potato mixture and shape it into a patty. If the mixture is a little sticky, wet your hands first. When the patty is shaped, press it into the panko bread crumbs, flip it over and repeat on the other side. Then roll the patty in the crumbs to smoothen out and coat the edges. Place the patty on the second dinner plate. Repeat this with the remaining mixture, and you should get about 8 patties altogether. Place them in the fridge for about half an hour to chill before frying.
Heat about 1 cm of rapeseed oil in a large frying pan and let it come to a shimmer. When it is sizzling hot, place four of the cakes into it – you do not want to overcrowd the pan. Cook them for about 3 minutes, turn them over carefully, and fry them for about the same amount of time on the second side. Using a slotted spoon, remove the cakes and place them on a kitchen roll lined plate to absorb excess oil. Repeat the process with the remaining cakes.
Serve them immediately, with tartar sauce. These cakes also go really well with a nice crisp salad, or some peas and green beans with a little fresh dill, lemon and olive oil mixed through.