Spread the canola oil over the entire surface of a 33 x 23 centimeter rimmed sheet pan.
Add the nine frozen patties to the sheet pan and cook for 12 minutes. Remove from oven and allow them to cool slightly. Turn the oven down to 375F.
Whisk together the eggs, sour cream, oregano leaves, granulated garlic and salt.
Use the bottom of a cup (or your hands) to press the cooled hash brown patties down so that the potatoes cover the entire surface of the sheet pan evenly. Make sure to patch up any holes with small pieces of hash brown.
Scatter the green pepper, onions and ham over the top of the hash brown crust.
Gently pour the egg mixture over the top of the hash brown base and scatter cheese over.
Carefully transfer the baking sheet on to the middle rack of the oven and cook for 18-20 minutes. The egg will be set in the centre.
After cooling slightly, run a knife around the perimeter of the pan to loosen the edges. Cut into six equal piece and serve.