1) Cut each courgette in half crosswise. Using a melon baller, carefully scoop out the courgette flesh, leaving about 1/2 cm of flesh intact on all sides and leaving the courgette closed at the bottom of each half. Reserve the flesh for another use, or discard. Reserve the courgette tubes.
2) Heat the oil in a heavy skillet over medium-high heat. Add the onions and cook, stirring, until they are soft and translucent, about 3 minutes. Add the garlic and cook for 2 minutes more. Add the minced beef, cumin, coriander and red pepper flakes, and cook until the meat is just done and no longer pink, 4 to 5 minutes. Add the bulgur, diced tomatoes and currants, and cook for an additional 2 to 3 minutes. Remove from the heat and stir in the pine nuts and parsley. Let the mixture cool slightly, about 5 minutes. Using a small spoon or clean hands, gently stuff the courgette halves with the beef mixture.
3) Place the courgette halves in a 23-by-33 cm glass baking dish. Combine the reserved tomato juice, tomato sauce and salt and pour over the courgettes. Cover tightly with foil and place in the oven. Bake for 20 minutes. Remove from the oven, uncover and rotate the courgettes. Re-cover, return the dish to the oven and bake for an additional 20 to 25 minutes, until the courgettes are cooked through but still slightly firm. Place the two vegetable halves on a plate and serve with some tomato sauce.
One serving is two courgette halves and 3 tablespoons of tomato sauce.