01 -
Preheat oven to 175°C. Lightly grease a 23×33-centimetre baking dish with butter or nonstick spray.
02 -
Melt butter in a large skillet over medium heat. Add diced onion and breakfast sausage. Cook, stirring occasionally, until sausage is browned and onions are softened. Drain excess grease.
03 -
Evenly layer the cut biscuit dough pieces at the bottom of the prepared baking dish.
04 -
Spoon the cooked sausage and onion mixture over the biscuit dough, distributing evenly.
05 -
In a medium bowl, whisk together eggs, whole milk, and dried oregano until thoroughly combined. Pour this mixture evenly over the sausage layer.
06 -
Scatter shredded cheddar cheese over the top, then pour warmed country gravy evenly across the casserole.
07 -
Transfer the baking dish to the oven. Bake for 30–40 minutes or until golden brown on top and the casserole is set in the centre.
08 -
Allow casserole to rest for several minutes before slicing. Serve warm.