Prepare Croustades and Mushroom Filling. Preheat oven to 350 degrees F.
Place prepared croustades on baking sheets (no need to thaw), and fill each with a heaping tablespoon of the Mushroom Filling. (Use a small spoon to fill the croustades with the mushroom mixture. Mound the filling slightly.) Sprinkle with Parmesan cheese and dot with butter. Bake approximately 10 minutes or until heated and cheese is melted. Sprinkle with minced parsley leaves.
Makes 24 Mushroom Croustades (allow 2 to 3 per serving).
Preheat oven to 375 degrees F. Coat the inside of 24 (2-inch) muffin cups generously with the butter. Using a 2 1/2-inch to 3-inch plain round cutter, cut out a circle from each bread slice. Using fingertips, press a circle of bread gently but firmly into each muffin cup so that it fits snugly. Bake 8 to 10 minutes until bread is golden brown. Remove from oven and cool.
NOTE: These may be wrapped and frozen at this point. Croustades freeze very well. Without defrosting them, fill them with the duxelles mixture and heat as described above. This way you are able to make a batch or two in advance.
In a large frying pan, melt the 4 tablespoons butter. Add shallots and cook three minutes stirring frequently. Add mushrooms, increase heat to moderately high and cook 8 to 10 minutes, stirring frequently until some water cooks out of mushrooms and is evaporated.
Remove skillet from heat. Sprinkle flour over mushrooms and stir in. Put skillet over moderate heat, gradually stir in cream and then cook, stirring constantly, until mixture thickens and simmers for 2 to 3 minutes. Remove from heat, stir in salt, cayenne, parsley, chives, and lemon juice.
NOTE: Allow to cool before filling croustades. It can also be transferred to a bowl, covered with plastic wrap and refrigerated at this point for 1 to 2 days.
* I like to use Shiitake mushrooms
Mushroom Croustade Recipe: https://whatscookingamerica.net/mushroomcroustade.htm