Preheat the oven to 200C/400F. Prick the potatoes a few times with a fork and place in the oven. Cook for 60-90 minutes (depending on the size of the potatoes) until cooked throughout.
Once cooked, remove from the oven and very carefully (use a kitchen towel to protect your hand), slice the top off the potatoes, then scoop out most of the potato and place in a medium-sized bowl.
Add the butter to the potato in the bowl and mash together, then stir in the cheese and half the bacon.
Spoon the mashed potato back into the potato skins, using a spoon to shape out a well for the eggs. You may not need all of the mashed potato (chef's treat!).
Crack an egg and pour the white into a small bowl. Keep the yolk separate in the shell for now (prop it up in a small bowl or dish). Pour the white into one of the wells in the potato. Repeat with the remaining two eggs so all of the potatoes have the egg white in.
Place the potatoes on a baking tray and place back in the oven for 9-11 minutes, until the white is almost set (just a little bit of jiggle).
Remove from the oven and carefully add the yolk to the top of each egg white. If you like, you can slit the white first with a knife to make a little space for the yolk to nestle into.
Place back in the oven for 3-4 minutes, until the top of the yolk is set, but it's still soft inside.
Sprinkle with the remaining bacon , the chopped spring onions and a good pinch of salt and pepper, then serve immediately.
Getting a runny yolk
It's really difficult to get a runny yolk if you're baking the eggs without separating out the yolks. The main reason for this is that the potato insulated the egg white, so it takes time for it to get hot and cook through. If the yolk is sitting on top the whole time the white is cooking, it will not be runny. The yolk will probably also have a hard layer on top. It's for this reason I separate the yolks from the white, to give time for the whites to cook through first. You can cook the white until they're almost completely cooked before adding the yolk (they'll finish cooking when the yolk is on top), or you can cook the whites until they're completely firm before adding the yolk (they can take another few minutes in the oven, no problem)..
Why prick the potatoes?
I've forgotten to prick my potatoes many times, and ended up with a potato explosion. They may explode in the oven, or explode on you when you come to take them out of the oven. And nobody wants scalding hot potato scattered all over them. Prick the potatoes with a fork at least 3 or 4 times to prevent them exploding..
You can use vegetarian cheddar and omit the bacon completely. Give the potatoes an extra little zing if you like by sprinkling on some smoked paprika before serving..
Make the potatoes right up until the point you have filled them with the bacon-potato mixture. At this point the potatoes can be cooled, covered and refrigerated for up to a day.Place the potatoes on a tray in the oven at 200C/400F for 10 minutes heat through a little before adding the egg whites and continuing with the recipe..
Leftover tops of the potato?
Save them, and either fill them with any leftover mashed potatoes, or fill them with grated cheese. They can then be covered and refrigerated for up to a day, then grilled (broiled) for 4-5 minutes to heat through. Bonus potato skins!!.Nutritional Information is per stuffed potato.