Langostino Bisque

Name: Langostino Bisque
Ingredients: 2 tablespoons butter; 1 medium sweet onion, coarsely chopped; 1 cup chicken bone broth; 1 cup clam juice; 0.5 cup coarsely chopped fresh mushrooms; 0.5 cup coarsely chopped celery with leaves; 0.5 cup coarsely chopped carrots; 0.5 cup coarsely chopped red bell pepper; 0.5 teaspoon ground Aleppo pepper, or more to taste; 0.25 teaspoon salt, or more to taste; 0.25 teaspoon freshly ground black pepper; 1 (12 ounce) package frozen pre-cooked langostinos (such as Trader Joe's®), thawed, divided; 1 cup heavy whipping cream; 0.5 cup Marsala wine; 1 cup croutons