Begin by preparing the potatoes. Rinse them thoroughly and place them—unpeeled—into a large pot. Cover with cold water and bring to a boil. Once boiling, cook for approximately 20 minutes or until the potatoes are tender enough to be pierced with a toothpick. Drain them and allow to cool slightly before peeling.

Using a potato masher or a fork, mash the peeled potatoes until smooth. Transfer the mash to a saucepan, add in the milk, grated Parmesan cheese, a pinch of nutmeg, salt, and pepper. Stir everything together over low heat for 1–2 minutes, just enough to blend the flavors and thicken slightly. Set aside to cool completely.

Meanwhile, prepare the savory filling. Dice the onion, carrot, and celery into small pieces. Heat 2 tablespoons of extra virgin olive oil in a pan and add the chopped vegetables. Sauté over low heat for 4–5 minutes until softened and aromatic. Increase the heat and add the ground beef. Cook until the meat is nicely browned, about 6–7 minutes, stirring occasionally. Season with salt, pepper, cumin, and ground coriander seeds. Once fully cooked and fragrant, remove from heat and let it cool.

To assemble the croquettes, lightly moisten your hands to prevent sticking. Take a spoonful of the mashed potato mixture and flatten it into your palm, creating a shallow well in the center. Place a spoonful of the beef filling in the center, then fold the potato around the filling to seal. Shape into small, thick discs. Repeat until all the potato and filling is used.

Pour the breadcrumbs onto a tray and gently press each croquette into the crumbs, turning to coat all sides evenly. Place the prepared croquettes onto a baking tray lined with parchment paper. Drizzle lightly with the remaining olive oil.

Bake in a preheated oven at 180°C (350°F), using the static function, for approximately 20 minutes. Turn each croquette halfway through cooking with a flat spatula to maintain their shape and ensure even browning. Once they are golden and slightly crisp, remove them from the oven. Lightly season with salt, allow to rest for a few minutes, then serve warm.