Makes 48 tartlets.
These received rave reviews! They require a fair amount of time but are, simultaneously, really easy. These came from a great book I have called Cocktail Parties Straight Up. The "make-ahead factor" included below is one of their great tips.
8 oz. cream cheese, softened
1/2 stick butter, softened
1-1/2 c. all-purpose flour
1/4 t. salt
2 T. butter
16 oz. (roughly 7 c.) mixed wild mushrooms, finely chopped
1 c. chopped green onions
4 T. balsamic vinegar
2 eggs, lightly beaten
2 t. all-purpose flour
1/2 t. dried thyme
1/4 t. salt
1/2 c. shredded Swiss cheese
1/4 c. shredded Parmesan cheese
Prepare the crust by beating the cream cheese and butter until smooth. Add the flour and salt and mix until well blended. From the mixture into a ball, cover, and chill 1 hour or overnight.
Preheat oven to 375 degrees.
For the filling, melt butter over medium heat in a large saucepan. Add the mushrooms and green onions, and cook until the mushrooms are tender, 5-10 minutes. Drain off any excess liquid, then add balsamic vinegar and stir thoroughly. Cook for 1 more minute. Let the mixture cool slightly.
In a large bowl, mix the eggs, flour, thyme, and salt with a spoon. Stir in the cheeses, then stir in the mushrooms.
Divide the chilled dough into 48 pieces. Press each piece into the cup of an ungreased mini muffin tin so it covers the bottom and sides. This does not have to be precise -- the dough puffs a bit when baked and is surprisingly sturdy.
Spoon the mushroom mixture into the cups so it's level with the top of each cup. Bake until the tart crusts are puffed and golden brown, 15-20 minutes.
Make-Ahead Factor: The dough can be made up to 2 days ahead and kept covered and refrigerated. The cooked tartlets can be refrigerated for 1 day or frozen for up to 2 weeks. Warm them in a 300 degree oven for 10-15 minutes if tarts were refrigerated, 20 to 25 if frozen.