Miso Butter Mac and Cheese

Name: Miso Butter Mac and Cheese
Ingredients: 10 oz elbow pasta; 2 ½ Tbsp unsalted butter; 2 ½ Tbsp all-purpose flour; 1 ¾ cups milk (warmed slightly); ¼ cup cream or half-and-half; ¼ cup sweet white miso paste (or to taste; alternatively 2 Tbsp red miso paste); 1 tsp soy sauce; 1 cup shredded sharp cheddar cheese; 1 ¼ cups shredded mozzarella cheese; ¼ tsp kosher salt; freshly ground black pepper (to taste); 2 Tbsp finely chopped chives; 1 cup panko breadcrumbs; 1 Tbsp melted butter; pinch garlic powder (optional); sprinkle Parmesan (optional)