Peel and chop the potatoes, then boil them in salted water until tender, about 10 minutes. Drain well and mash until smooth. Let cool slightly.
While the potatoes cook, steam or boil the chopped carrots and zucchini until soft, about 8-10 minutes. Drain any excess water and set aside.
In a large mixing bowl, combine the mashed potatoes, cooked vegetables, beaten eggs, chopped parsley, salt, pepper, and smoked paprika. Mix thoroughly until everything is well incorporated and the mixture holds together when pressed.
Shape the mixture into small oval or round croquettes, about 2 inches long. Place them on a tray and refrigerate for 15-20 minutes to firm up.
Pour the panko breadcrumbs into a shallow dish. Remove the croquettes from the fridge and gently roll each one in the breadcrumbs until evenly coated.
Heat the neutral oil in a frying pan over medium-high heat until it reaches about 180°C (356°F). You can test by dropping a small piece of bread—if it sizzles and turns golden in 30 seconds, the oil is ready.
Carefully add a batch of croquettes to the hot oil, frying in batches to avoid overcrowding. Cook for 3-4 minutes, turning occasionally, until they are golden brown and crispy.
Using a slotted spoon, transfer the cooked croquettes to a plate lined with paper towels to drain excess oil. Repeat with remaining croquettes.
Serve the croquettes hot, garnished with extra parsley or lemon wedges if desired. Enjoy their crispy exterior and tender, flavorful interior.
