Stuffed pastry with Swiss chard and feta cheese makes a great appetizer or serve for any meal of the day. This recipe is an adaption of a traditional Israeli snack called Bureka. Serve with yogurt tahini spread, olives, and hard-boiled eggs, to create the perfect al fresco meal. Please don't be discouraged by the long prep time. Most of the prep time is waiting for the dough to chill, or the vegetables to cool. With the cooling and chilling time in mind, just make sure you have plenty of time to make these savory stuffed pastries. This stuffed pastry recipe can be made in advance and frozen for up to one month for your convenience. This recipe is slightly adapted from Breaking Breads by Uri Scheft.
Turn the heat to medium and heat the olive oil in a large 10-inch skillet. Add the minced onion, celery and Swiss chard stems and 1/4 tsp of Kosher salt to the skillet and cook until softened, about 5-8 minutes. Stir occasionally to prevent browning.
Add half of the Swiss chard greens and 1/4 tsp Kosher salt, and stir and cook until the leaves have wilted. Once the first batch cooks down, add the remaining Swiss Chard and cook until it is all wilted.
Scrape in the spinach leaves in the skillet with the vegetables in two batches. Once the spinach is heated and wilted, add the lemon juice. Stir and taste for seasoning. Add more salt and other seasonings if needed. Remember, the cheese in the filling will add a lot of salt to the bureka, so keep that in mind when you are tasting the vegetables.
Preheat the oven for at least 30 minutes to 400°F (200°C / Gas Mark 6). If you have baking stones add them on the oven racks when you turn the oven on. Or turn a rimmed baking sheet large enough for two or three bureka to fit, upside down on an oven rack. The stones or the baking sheet will get good and hot and help create a crisp crust. If you only have one stone bake the burekas in batches.