Peel and cut the potatoes into even chunks, then place them in a pot of cold salted water and bring to a boil. While the potatoes cook (about 15-20 minutes until fork-tender), begin the meat filling: heat olive oil in a large skillet over medium heat and sauté the diced onion for about 3 minutes until softened and fragrant. This parallel timing means your potatoes and aromatics will be ready around the same time. When the potatoes are tender, drain them well and set aside to cool slightly—they'll be easier to mash when still warm but not steaming hot.

Add the chopped mushrooms to the softened onion and cook for 6-7 minutes, stirring occasionally, until the mushrooms release their moisture and begin to brown slightly—this develops deep umami flavor. Add the ground turkey, breaking it apart with a spoon as it cooks, and stir in the paprika, dried herbs, salt, and garlic powder. Cook for about 5 minutes until the turkey is no longer pink. Sprinkle the flour over the mixture and stir well, cooking for 1 minute to create a light gravy that will thicken the filling. Remove from heat and let cool for a few minutes before the next step.

Transfer the cooled meat mixture from Step 2 to a food processor and add the tomato paste. Pulse until the mixture becomes sticky and cohesive—this helps bind everything together and distributes the umami flavor throughout. The mixture should hold together when pressed but still have some texture. Don't over-process; you want it to remain slightly chunky, not a smooth paste. Set the filling aside to cool completely while you prepare the potato dough.

Mash the cooled potatoes from Step 1 until smooth and fluffy, then add the egg, salt, and all-purpose flour. Mix gently with a wooden spoon or your hands until a soft dough forms—I find that mixing by hand gives you better feel for when the dough comes together without overworking it. The dough should be slightly sticky but manageable; if it's too wet, add a touch more flour, a tablespoon at a time. Don't knead it excessively, as this will develop gluten and make the cakes tough instead of light and fluffy.

Divide the potato dough in half and gently roll each half into a log about 8 inches long. Cut each log into 7 equal pieces to yield 14 portions. Working with one piece at a time, flatten it into a thin round about 3 inches across, place about 1 tablespoon of the meat filling from Step 3 in the center, then fold the edges up and seal them together to create a patty—I pinch the edges firmly to ensure they stay sealed during frying, especially since you want the filling to stay inside. Set each finished patty on a parchment-lined tray.

Heat the olive oil in a large skillet over medium-high heat until shimmering. Working in batches to avoid crowding, carefully place the patties in the hot oil and fry for 2-3 minutes per side until golden brown and crispy on the outside. The exterior should be deeply golden and slightly crispy while the inside stays soft and the filling heats through. Transfer finished cakes to a paper towel-lined plate to drain excess oil, and serve warm.