Preheat the oven to 375 degrees. In an extra-large mixing bowl, whisk together the sour cream, milk, butter, hot sauce, worcestershire, thyme, garlic, salt, pepper, until smooth.
16 ounces full fat sour cream, 1 ½ cups whole milk, 1 Tablespoon EACH hot sauce & Worcestershire sauce, 1 teaspoon EACH dried thyme, granulated garlic, & Morton kosher salt*, fresh cracked black pepper, 4 Tablespoons salted butter, melted
Stir in the diced onions.
½ cup finely diced white onion, optional
Pour in all of the hashbrowns and fold until completely combined.
32 ounces plain frozen shredded hash browns*
Add the cheese and fold until combined.
12 ounces (3 cups) sharp cheddar cheese*
In a separate bowl, combine the panko, parmesan, and butter.
1 cup panko breadcrumbs, ½ cup grated parmesan cheese
Spray a 9 x 13 baking dish with nonstick cooking spray. Pour the potato mixture into the dish.
Top with the panko mixture.
Bake for about 60 minutes or until bubbling and golden. Cover loosely with foil if the top browns too quickly.