Mushroom and Spinach Tart

I find that the sheets of puff pastry you can buy are really versatile, especially for things like tarts, savoury tarts making excellent dinners.
For today's Mushroom and Spinach Tart, I soften about half a packet (150g) of mushrooms cut into quarters with a couple of sliced onions in a frying pan with oil and butter. Meanwhile, I wilt a packet of spinach (around 200g), drain and set aside. Once the mushrooms and onions have soften I add some chopped parsley, tarragon and seasoning, as well as the spinach, then turn up the heat while stirring to lose the excess liquid. Placing the pastry on greaseproof paper on a baking tray, I lightly score a border the width of a finger and dot inside it with soft cheese before piling the mushroom mixture on top. After 20 minutes in the oven I get a vegetarian midweek dinner that even a carnivore would devour hungrily...