Preheat your oven to 350°F and butter a 9x13 baking dish generously. Spread the frozen hashbrowns across the bottom in an even layer without thawing them first.

Heat butter in a large skillet over medium heat and sauté the diced onion and red bell pepper until softened, about 4-5 minutes. Stir in the chopped smoked turkey strips and cook 2 more minutes until warmed through.

Whisk together the 8 eggs, heavy cream, whole milk, salt, black pepper, and garlic powder in a large bowl until smooth. Fold in the sharp cheddar and mozzarella cheeses until evenly distributed throughout the mixture.

Spread the sautéed vegetable and turkey mixture over the hashbrowns in your prepared dish. Pour the golden breakfast hashbrown casserole egg and cream custard over everything, pressing gently so the liquid reaches the bottom layer.

Sprinkle the paprika evenly across the top and bake uncovered for 40 minutes until the center is set and edges turn golden brown. The casserole should jiggle slightly in the very center when removed from the oven.

Let rest 5 minutes before garnishing with fresh chopped chives and serving warm. This family brunch bake stays warm for up to 20 minutes if your guests run late.