Spinach-feta turnovers

If you've eaten these at Greek bakeries, you know them as spanakopita. In Armenian, we call them beoregs, in Bulgarian banitza.
Needless to say I have had several variations on the theme and some of the best spinach pies I've eaten have been my mom's or those still piping hot from vendors in Bulgaria, where the local sirene (known as feta to the rest of the world) is to die for.
Most of the Armenian moms and grandmoms you'll speak to have their own recipe and will defend it to the death.
So when I saw a recipe for these ones in Martha Stewart's Everyday Food magazine, I was hesitant. How could Martha Stewart improve on a recipe honed and perfected by centuries of women?
She did it again. The end result was amazing. My husband told me they are the best he's ever eaten, and his mom is a fabulous cook.

Adapted ingredients:
2 tablespoons olive oil
2 medium onions, chopped
2 garlic cloves, minced
2 boxes (10 ounces each) frozen chopped spinach, thawed and squeezed dry (the recipe calls for four, but I used two and still had a lot of leftover filling)
2 cups crumbled feta
2 to 4 tablespoons fresh lemon juice
1/8 to 1/4 teaspoon cayenne pepper
Kosher salt and ground pepper
1 large egg, beaten with 2 tablespoons of water for egg wash
All-purpose flour for work surface
1 box of frozen puff pastry (17.3 ounces), thawed but still cold

Adapted directions:
Heat oil over medium, add onions and garlic. Stir occasionally until soft, about 5 to 7 minutes.

Transfer to a large bowl and add the spinach, feta, lemon juice and cayenne. Season with salt and pepper - don't forget to taste - and set aside.

Preheat oven to 375 degrees Fahrenheit with racks in upper and lower thirds. Roll out each portion of dough, still folded in thirds, on a lightly floured work surface, into a 12-inch square. Some puff pastries are already rolled out into this square. Cut each into quarters to form total of 8 equal squares.

Dividing the filling evenly, spoon it into the centre of each square. Brush the two adjoining edges of each square with some egg wash. Fold edges over filling to form a triangle. Press firmly to seal and then using a floured fork, crimp the edges.

Transfer them to two baking sheets, brush the tops with the egg wash and bake until golden and puffy. The recipe says 35-40 minutes, rotating sheets halfway through. However, when I have made a smaller batch, it has taken me as little as 20 minutes. Best to keep an eye on the oven.

To freeze the unbaked turnovers, line a baking sheet with parchment paper, place the turnovers on top and put them in the freezer until frozen. Once they are hard, wrap them individually in plastic wrap or store them in a resealable plastic bag in the freezer for up to two months.

Substitutions:
I played around with the seasonings as per my taste, adding more cayenne and black pepper than most people may prefer.

Would I make this again?
I plan to as soon as this weekend to freeze them for when the baby arrives and the last thing I want to do is make food. The first couple of times I made these I made extra and froze them, and they were just as tasty as when baked fresh.

Grade:
Five stars out of five. These buttery spinach-feta turnovers have just the right tang and bite with the lemon juice and cayenne pepper. And after decades of eating beoregs and spanakopita, I know my spinach pies and these are divine.