Hash Brown Crust Quiche with Smoked Salmon

Name: Hash Brown Crust Quiche with Smoked Salmon
Ingredients: 6 tablespoons unsalted butter, melted and divided; 8 cups frozen shredded hash browns, thawed and squeezed dry; 3/4 cup grated Parmigiano-Reggiano cheese, divided; 2 teaspoons kosher salt, divided; 1 teaspoon garlic powder; 3/4 teaspoon black pepper; 8 large eggs; 1/2 cup heavy whipping cream; 1 (8-ounce) container crème fraîche, at room temperature, plus more for serving; 6 ounces sliced smoked salmon, divided; 2 tablespoons drained nonpareil capers, plus more for garnish; 1 tablespoon chopped fresh dill, plus fronds for garnish; Thinly sliced red onion and Everything bagel seasoning, for garnish