Begin by preparing the zucchini boats. Preheat your oven to 400°F (200°C). Wash and dry the zucchini, then slice them in half lengthwise. Scoop out the center flesh using a spoon, creating a hollowed-out boat shape. Be careful not to pierce the skin. Chop the scooped zucchini flesh into small pieces, either with a knife or food processor, and set aside.

To make the filling, heat olive oil in a large skillet over medium heat. Sauté the chopped onion for about 3 minutes, or until it softens. Add the minced garlic and chopped zucchini flesh, cooking for another 5 minutes while stirring occasionally.

Stir in the lentils, walnuts, crushed tomatoes, balsamic vinegar or soy sauce, oregano, salt, and black pepper. Let the mixture simmer on medium heat for about 10 minutes to allow the flavors to blend. Turn off the heat and mix in the grated parmesan or dairy-free cheese. Taste and adjust the seasoning as needed.

Assemble the zucchini boats by placing the hollowed shells on a baking tray. Fill each shell with the lentil mixture, pressing it in gently. For extra indulgence, sprinkle additional cheese on top. Bake in the preheated oven for about 20 minutes, or until the zucchini are tender when pierced with a fork.

Once baked, transfer the zucchini boats to a serving platter and garnish with fresh parsley. Serve with lemon wedges for a zesty finish. These stuffed zucchini are delicious on their own or paired with Greek yogurt, tzatziki, or a yogurt-tahini sauce.