Seafood Gumbo

Ingredients

• 2 pounds unpeeled fresh large shrimp
• 1/2 cup butter, divided
• 2 (32-ounce) cartons chicken broth
• 1 pound andouille sausage, sliced
• 1/2 cup vegetable oil
• 1 cup all-purpose flour
• 2 cups finely chopped yellow onion
• 1 cup finely chopped green bell pepper
• 1 cup finely chopped celery
• 2 tablespoons minced garlic
• 1 (12-ounce) bottle amber beer
• 1 tablespoon Cajun seasoning
• 2 teaspoons Worcestershire sauce
• 1 teaspoon dried thyme
• 2 bay leaves
• 1/2 cup green onion tops
• 1/4 cup chopped fresh parsley
• 1 pound lump crabmeat
• Cooked rice for serving