1. Butter: Spread the cut side of each split English muffin evenly with 1 teaspoon of softened butter.

2. Arrange: Place the muffins, buttered side facing down, into a lightly greased 13x9x2 inch casserole dish.

3. Brown: Cook the pork sausage in a skillet over medium-high heat until completely browned, stirring frequently to crumble the meat.

4. Drain: Pour off any excess grease from the skillet to keep the bake crisp.

5. Layer: Evenly divide the crumbled cooked sausage, drained green chilies, and shredded cheddar cheese over the top of each muffin half in the dish.

6. Whisk: Combine the sour cream and 12 beaten eggs in a medium mixing bowl, whisking together until the mixture is uniform and smooth.

7. Pour: Pour the egg and sour cream mixture evenly over the layered casserole ingredients.

8. Chill: Cover the dish tightly and refrigerate it in the fridge for 8 hours (or overnight).

9. Rest: Remove the casserole from the refrigerator before baking and let it stand at room temperature for 30 minutes. Meanwhile, preheat your oven to 350°F / 180°C / Gas Mark 4.

10. Bake: Place the dish uncovered into the preheated oven and bake for 35 to 40 minutes until the center is set and the cheese is golden.

11. Dig In: Slice up this simple breakfast treasure and enjoy a completely stress-free morning!