Preheat oven to 200°C. Pour boiling vegetable broth over the fonio and cover and let it steep for 10 minutes. In the meantime, peel and finely dice the onion and garlic. Dice tomatoes.
Heat olive oil in a pan and sauté onions and garlic until translucent. After steeping time, fluff the fonio with a fork.
Halve the zucchini lengthwise, scoop out the zucchini with a spoon and season lightly with salt. Place the zucchini halves in an oiled baking dish.
Fold onions, tomatoes, pine nuts and oregano into the fonio. Add lemon juice, tomato paste and parsley. Season with salt and pepper. Pour the fonio mixture into the zucchini halves and crumble the feta cheese over the top. Cook in the oven for about 15-20 minutes.