1. Preheat the oven to 350°F.

2. Using an electric mixer, beat the eggs, salt, and pepper. Add the milk and cream; mix well. Set aside.

3. In a hot pan, melt the butter. Add the mushrooms and cook until browned on both sides. Remove from heat.

4. Using a food processor, coarsely chop the mushrooms and add dried tarragon. Set aside.

5. Line a buttered and floured tart mold with the puff pastry. Prick the bottom of the pastry with a fork.

6. Bake for 6 minutes to pre-cook the pastry. If it has puffed, flatten with a fork.

7. Fill the mold halfway with the chopped mushrooms. Pour in the egg mixture to fill the pastry almost to the rim.

8. Bake for 20 minutes.

9. Remove from the oven and serve.