Easy Classic Tuna Noodle Casserole with Crispy Topping

Ingredients

• 12 oz (340 g) wide egg noodles
• 2 tablespoons unsalted butter
• 1/2 cup (75 g) finely diced yellow onion
• 1/2 cup (55 g) finely diced celery
• 1 can (10.5 oz or 298 g) condensed cream of mushroom soup
• 3/4 cup (180 ml) whole milk, plus more if needed
• 1/3 cup (80 g) sour cream
• 1 cup (115 g) shredded sharp cheddar cheese
• 2 cans (5 oz or 142 g each) tuna, drained and flaked
• 1 1/2 cups (210 g) frozen peas
• 1/2 teaspoon garlic powder
• 1/2 teaspoon black pepper
• 1/4 teaspoon kosher salt, plus more for pasta water
• 1 cup (45 g) crushed buttery crackers
• 2 tablespoons unsalted butter, melted
• 1 tablespoon chopped parsley, optional