Mushroom bourekas

If working with frozen dough, defrost your phyllo dough overnight in the fridge, or leave on the counter for a few hours.Preheat your oven to 350 degrees Farenheit.Chop onions finely.Preheat a pan over medium heat. Once pan is hot, add your margarine and oil and let it melt. Add onions to the pan and cook over medium heat for 5-10 minutes, until they are starting to turn translucent. Lower heat to low, and let onions reduce and caramelize for 20 minutes.Slice mushrooms, taking care to not slice too thinly or too thickly. Chop the larger slices into smaller pieces. You want your mushrooms to retain their meatiness, but also be small enough to fit into phyllo triangles.Add mushrooms to the pan with the onions, and raise heat to medium. Let cook until mushrooms brown, about 10-15, stirring occasionally.Add herbs, salt, and lemon, tasting and correcting flavours as necessary. You want the filling to be rich, earthy, sweet and salty, but with a burst of bright acidity that cuts through the meatiness.Prepare your phyllo dough. Cover your work surface with parchment paper. Line two cookie sheets with parchment paper, and oil them slightly. If you haven’t done so yet, melt 1 tablespoon of margarine in a small bowl, and dilute it with 1 teaspoon of water.Carefully spread out one phyllo sheet on your work surface, covering the rest with a towel so they don’t dry out. With a pastry brush, lightly brush your sheet with the melted margarine and water mixture. Cover it in half lengthwise, and dab lightly with the margarine mixture.To prepare the bourekas, spoon 1 tablespoon of the mushrooms and onion filling at the right end of the strip. Fold the end of the strip diagonally over the filling to form a neat triangle, pushing in the corners to ensure it's nice and snug around the filling. Continue folding the strip over on top of itself, keeping it in a neat triangle after each fold, until you reach the strip’s end (take care to fold the triangles tightly around the filling, as phyllo dough without filling tends to dry out and crisp in the oven). If any errant dough remains at the end of your strip, cut it off. Brush your triangle with the margarine-water mixture, and lay out on the parchment paper-covered cookie sheet.Repeat as necessary, until you run out of dough or filling. Any remaining filling will taste great piled on toast.Bake the pastries for 15-20 minutes, until they are golden brown. Check periodically after 10 minutes to ensure the pastries are not burning.Serve bourekas warm, or hot, or in room temperature, with a light salad or a simple brothy soup. They taste best when eaten fresh, and do not keep well. Reheat the bourekas only in the oven – the microwave will make it soggy.