Vegan Stuffed Butternut Squash with Mushrooms and Couscous

Name: Vegan Stuffed Butternut Squash with Mushrooms and Couscous
Ingredients: 3¼ Pounds (1.5 kg) butternut squash, cut in half lengthways and seeds and fibers scooped out; 1 small handful dried porcini mushroom; 1 red onion, finely chopped; 2 cloves garlic, finely chopped; 5 pieces sun-dried tomatoes, chopped; 3½ Ounces (100 g) couscous; 2 sprigs of fresh rosemary, leaves picked and finely chopped; ¼ teaspoon chili powder; ¼ teaspoon ground coriander seeds; ½ handful walnuts, very coarsely chopped; olive oil; salt, black pepper to taste