The filling for mushroom tartlets is dead simple if you have a food processor and a bit of work if you do it all by hand as the onions and mushrooms need to be very finely chopped.
I use a basic pie dough for my pastry and bake them in mini tart tins. I follow the recipe on the Tenderflake box.
These are a great make ahead for the holiday season! Make them in November and freeze them. Reheat and serve!