Slice the eggplants lengthwise into thin slices, about 3/16 inch (4-5 mm) thick, using a mandoline or a sharp knife.

Lay out the slices, salt them lightly on both sides and let them sit for 30-60 minutes. Pat them very dry with paper towels.

Preheat the oven to 350-375°F (180-190°C). Arrange the slices on a parchment-lined baking sheet and brush generously with olive oil.

Bake for about 10 minutes, carefully flipping halfway through. Remove when lightly golden and soft, and let cool.

Grate the onion and zucchini and squeeze out as much liquid as you can. This step is important - otherwise the mixture will fall apart.

In a bowl, mix the beef, squeezed onion and zucchini, parsley, egg, garlic, tomato paste and spices. Taste and adjust the seasoning.

Shape small oblong meatballs, place one at the end of each eggplant slice and roll it up. Repeat until you run out of slices. Shape any leftover meat into small meatballs.

Heat the olive oil in a wide braiser or deep sauté pan, add the garlic and cook until fragrant.

Add the passata, tomato paste, water, sweet and hot paprika, salt and pepper. Simmer for about 10 minutes, until slightly reduced.

Arrange the rolls (and any extra meatballs) in the sauce in a single layer, seam side down.

Cover and cook over low heat for 1 to 1 1/4 hours, until the meat is cooked through and the sauce has thickened.

Serve hot, garnished with parsley leaves.