Greek Diner Meat and Spinach Pot Pies

Name: Greek Diner Meat and Spinach Pot Pies
Ingredients: 1 tablespoon EVOO; 2 pounds ground lamb, beef or chicken; 3 tablespoons butter; 1 tablespoon lemon zest; 1 1/2 teaspoons dried Greek oregano or marjoram, half a palmful; 4 cloves garlic, thinly sliced or chopped; 2 medium onion, chopped; Salt and freshly ground black pepper; 1/2 cup fresh flat-leaf parsley leaves and dill combined, finely chopped; 2 round tablespoons flour; About 2 1/2 cups chicken stock; Juice of 1/2 lemon; One 10-ounce package organic chopped frozen spinach, wrung dry in kitchen towel; 1 cup feta crumbles; 1 sheet puff pastry; Flour, for rolling; 1 egg, lightly beaten with splash of water