Thaw puff pastry sheets according to the package directions.
2 sheets frozen puff pastry
In a medium bowl, combine softened cream cheese, dill, onion powder, garlic powder, salt, and pepper, and two eggs. Mix until smooth.
8 ounces cream cheese, 1 teaspoon dried dill, 1 teaspoon onion powder, ¼ teaspoon garlic powder, ½ teaspoon coarse kosher salt, ¼ teaspoon freshly ground black pepper, 2 large eggs
Add in the spinach, crumbled feta, and crumbled bacon if using. Mix until everything is well combined.
4 cups chopped and packed fresh spinach, 1 ½ cups crumbled feta cheese, 4 strips cooked bacon
Once thawed, roll the sheet of puff pastry out on a lightly floured surface and cut it into 9 squares using a pizza cutter or sharp knife. Repeat with the other sheet of thawed puff pastry.
Grease your muffin pan with non-stick spray or cooking spray, then place a square of puff pastry into each greased muffin cup, letting the corners overhang.
Spoon about 2 ½ to 3 tablespoons of the spinach mixture into the center of each muffin cup.
Fold the overhanging puff pastry corners over the filling and pinch the edges together to seal them.
Place the muffin pan in the fridge for 30 minutes to chill, or freeze for 15 minutes if you're short on time.
Whisk the remaining egg with 1 teaspoon of cold water to make an egg wash. Use a pastry brush to brush the tops of each spinach puff with the egg wash for a golden brown finish.
Bake in a preheated oven at 400°F for 20-25 minutes, or until the pastry is puffed and golden brown.