Preheat your oven to 400°F (200°C). Lightly grease a large baking dish or line it with parchment paper to prevent sticking.

Rinse the zucchini under cool water and pat them dry. Trim the stem ends, then slice each zucchini in half lengthwise to create long boats.

Using a small spoon, carefully scoop out the center of each zucchini half, leaving about 1/4 inch (0.5 cm) thickness around the edges so the shells stay sturdy. Reserve the scooped zucchini flesh on a cutting board.

Finely chop the reserved zucchini flesh and set it aside; it will be added to the brisket filling so nothing goes to waste.

Arrange the hollowed zucchini halves cut side up in the prepared baking dish. Brush the insides and edges evenly with 1 tablespoon of olive oil (for brushing the zucchini), and sprinkle lightly with a pinch of the fine sea salt taken from the measured amount.

Place the baking dish with the zucchini shells in the preheated oven and bake for 10–12 minutes, just until they begin to soften but still hold their shape. Remove from the oven and set aside while you prepare the filling.

While the zucchini shells are baking, heat 1 tablespoon of olive oil in a large skillet over medium heat. Add the finely chopped yellow onion and cook for 4–5 minutes, stirring occasionally, until it turns translucent and slightly golden at the edges.

Add the minced garlic to the skillet and cook for 30–60 seconds, stirring constantly, until fragrant but not browned.

Stir in the chopped reserved zucchini flesh and cook for 2–3 minutes, allowing some of the moisture to cook off and the vegetables to soften.

Add the cooked shredded brisket to the skillet, gently breaking up any larger pieces so they distribute evenly through the mixture.

Pour in the crushed tomatoes and add the tomato paste, stirring well until the brisket and vegetables are evenly coated in the tomato mixture.

Season the filling with smoked paprika, dried oregano, ground black pepper, and the remaining fine sea salt. Stir to combine the spices thoroughly with the brisket mixture.

Add the beef broth or stock to the skillet and stir again. Let the mixture simmer over medium-low heat for 5–7 minutes, stirring occasionally, until slightly thickened and saucy but not watery.

Taste the brisket filling and adjust the seasoning with a little more salt or pepper if desired, keeping in mind that the cheeses will also add some saltiness.

Remove the skillet from the heat and allow the filling to cool for 3–5 minutes so it is easier to handle when stuffing the zucchini shells.

Spoon the warm brisket mixture into each pre-baked zucchini shell, dividing it evenly among all the halves and gently pressing it down so it fills the hollows completely.

In a small bowl, combine the shredded mozzarella cheese and grated Parmesan cheese, tossing them together so they are evenly mixed.

Sprinkle the cheese mixture generously over the top of each stuffed zucchini, covering the brisket filling from end to end.

Return the baking dish to the oven and bake at 400°F (200°C) for 15–20 minutes, or until the zucchini are tender when pierced with a fork and the cheese is melted, bubbly, and lightly golden in spots.

Once baked, remove the brisket stuffed zucchini from the oven and let them rest in the baking dish for about 5 minutes so the filling can settle slightly.

Sprinkle the tops of the stuffed zucchini with the chopped fresh parsley for a bright, fresh finish just before serving.

Serve the brisket stuffed zucchini warm, using a spatula to lift each zucchini boat carefully from the baking dish onto plates, and enjoy immediately.