Preheat oven to 400 degrees. Lightly grease a 9-inch pie pan.
In a large skillet, brown beef, onion and seasonings over medium-high heat; drain excess grease with paper towels.
Add oatmeal while still hot. Spread mixture in prepared pie pan.
In a medium bowl, whisk together milk, eggs and pancake mix until well blended; pour over ground beef mixture in the pie pan then bake, uncovered, for approximately 25 minutes.
Carefully remove pie from oven and top with cheese while hot. Bake for another 5 minutes or until a knife inserted in the center comes out clean.
Cool for 5 minutes before digging in!