Begin by washing your potatoes, and scrubbing the peel either with a vegetable brush or the abrasive side of a clean sponge.
Pierce each potato with a fork once and then place on a microwaveable safe dish, pierced side up.
Microwave on high for approximately 10 minutes. Your microwave might have a baked potato setting, and cooking time may vary depending upon the size of your potatoes, and your microwave. You will know your potatoes are ready when a sharp knife inserted into the center meets little resistance.
While your potatoes are being microwaved, prepare the filling.
Wash your spinach and add it into a frying pan with the olive oil, parsley and the chopped white part of your green onions. Chop and reserve the green parts of your green onions as you will use those at the end. Add salt and pepper to taste to your vegetable mixture.
Cook for a few minutes until the spinach is quite soft but still a vibrant green; this should only take a few minutes.
Transfer the vegetable mixture to a sieve and press down with the back of a spoon in order to remove the excess water. Set aside.
When your potatoes are ready, remove them from the microwave and allow them to rest for 5 minutes.
Carefully, using a sharp knife, cut a slit lengthwise into your potato. This cut should go almost to the bottom of the potato, but leave about 1/2 inch on either end so that it retains its shape.
Using your hands, gently squeeze alongside the slit in order to break apart the potato. Be careful not to tear the skin.
Add 1 - 2 tablespoons of Greek yogourt to your potato and then top with the spinach mixture, dividing equally between the 2 potatoes.
Top each of the potatoes with crumbled feta, evenly distributed.
Broil for 1 - 2 minutes, watching carefully so that you don't burn the topping.
Garnish with the green part of your green onions, and serve.