Mushroom, Spinach & Crumbled Feta Pie

+ 1 red onion, sliced
+ 2 garlic cloves, minced
+ 1 tbsp olive oil
+ 1 red bell pepper, thinly sliced
+ 2 cups mushrooms, sliced
+ 1/4 cup vegetable stock
+ 3 cups spinach
+ sea salt and freshly ground black pepper, to taste
+ 1 sheet all-butter puff pastry
+ 3/4 cup feta cheese, crumbled
+ 1 egg, beaten

To make the mushroom-spinach filling: In a large skillet, heat oil over medium-high heat, add onions, and cook until golden. Add mushrooms, garlic, and bell pepper, and season to taste. Cook until the mushrooms are softened, then add the vegetable stock and simmer for 10 minutes. Add spinach, cook and stir until wilted, then remove from heat and set aside.

To make the pie: Preheat oven to 400ºF / 200ºC. Lay out the puff pastry on a piece of baking paper and spread the mushroom-spinach filling over the pastry, leaving a 2-inch (5 cm) border around the edge. Sprinkle the feta cheese on top and brush the border of the pastry with the beaten egg. Fold the pastry over the mushroom-spinach filling creating a pie. Brush the pie edges with the remaining egg and bake in the preheated oven for about 35 minutes. Enjoy!