Lentils with Butternut Squash and Merguez Sausage

Name: Lentils with Butternut Squash and Merguez Sausage
Ingredients: 1 pound merguez sausage; 1 medium onion, halved; 8 garlic cloves, peeled, 3 finely chopped; 1 carrot, cut into chunks; 1 pound French green (Le Puy) lentils (2 1/4 cups), picked over and rinsed; 3 tablespoons extra-virgin olive oil; Kosher salt; 1 pound butternut squash, peeled and cut into 1/2-inch chunks; 2 teaspoons ground cumin; 1 tablespoon plus 1 teaspoon sweet paprika; 1 teaspoon Marash or Aleppo pepper (see Note); 1 teaspoon harissa; 2 cups vegetable stock or water; One 14-ounce can crushed tomatoes; 1 jalapeño, seeded and finely chopped; 2 tablespoons fresh lemon juice, plus lemon wedges for serving; Freshly ground pepper