Preheat oven to 400F.
Line a baking sheet with parchment paper.
Using a rolling pin, lightly roll out the puff pastry to approximately 11x11.
Cut in half.
Transfer to previously lined baking sheet and bake for 8 minutes.
In the meantime, prepare the filling.
Heat olive oil in a large nonstick skillet; add spinach and garlic and cook for 2 minutes, or until spinach is wilted. Stir frequently.
Stir in the crumbled feta and continue to cook for 30 seconds; remove from heat and set aside.
Take the puff pastry out of the oven and using a fork or a spoon, deflate the center of the puff pastry, leaving about a 1-1/2 inch puffed-up border on all sides.
Divide up the filling and add it to the center of both pastries.
Make a well in the center of the filling and crack an egg inside of the well.
Bake for 10 to 12 minutes, or until the puff pastry is a nice golden brown.
Remove from oven and let stand about 3 minutes.
Sprinkle with a bit of salt and fresh ground pepper.
Cut each pastry into 4 wedges.
Serve with a side of plain yogurt.