Preheat the oven to 400 degrees F.
Spray the cavities of a 12 cup muffin pan generously with nonstick cooking spray.
Add one round of Canadian bacon to each cavity, gently pushing down to meet the bottom and form a cup.
With the extra 8 slices, tear and use them to fill any space on the sides of the muffin cavities. It doesn't need to look perfect!
Crack one egg in each Canadian bacon cup and lower in.
Divide the grated cheese evenly among the egg cups and top with the salt and pepper.
Garnish each with a few slices of spring onion.
Bake for 15-25 minutes, depending on how set you want your yolks. Check them at 15 and go from there.
These keep refrigerated for up to one week.