Preheat the oven to 425 degrees F (220 degrees C). Line a 10x15-inch rimmed baking sheet with foil and coat with cooking spray.
To thaw hash browns, place in a large microwave-safe bowl. Microwave on High, stirring once, until thawed, about 6 minutes.
Stir oil and 1/4 teaspoon each salt and black pepper into hash browns until combined; turn out onto the prepared baking sheet. Press mixture into bottom and 1 inch up sides of baking sheet to make a crust. Bake until edges are browned, 20 to 25 minutes.
Meanwhile, for sauce, blend tomatoes in a small blender or food processor until smooth.
Whisk together eggs, garlic powder, and remaining 1/4 teaspoon each salt and black pepper in a medium bowl.
Spoon sauce onto crust, spreading to edges. Pour egg mixture on top of sauce. Sprinkle with Cheddar cheese, Canadian bacon, and bell pepper and onion blend. Bake until eggs are set, cheese is melted, and vegetables are heated through, 10 to 12 minutes.
Garnish with chives and/or Parmesan cheese. Slice into 6 pieces.
