Peel and wash the potatoes and then grate them finely. Crack 6 eggs open and whisk together. Season with salt and pepper generously. Add the grated potatoes to the eggmix and stir everything together. Taste and add more salt and pepper if you want. If you do want to taste raw eggs, bake one cake and taste if it needs additional seasoning
Boil the other 6 eggs till hard. Peel and keep yolks and whites separate, mashing them finely with a fork.
Cut the spring onion and the chili pepper finely and stir through the creme fraiche together with the mustard. Add the trout eggs if you want. Since these are very salty, make sure you keep that into consideration when your seasoning your potatoes. Taste your creme fraiche mix and add seasoning where needed.
Heat a frying pan on medium heat, add oil to the pan and with a spoon form little rounds of your potato-egg mixture. You can use a baking ring if you want or go freeform. Bake until golden brown, flip and bake the other side until done and transfer to a baking tray.
Once all your potato cakes are done you can leave them on the baking tray until you're ready to eat. Heat them through in the oven and serve with the creme fraiche. Add the egg crumbles to your plate and - if using - you can also add some additional trout eggs too.