10 ounces mushrooms, cleaned and patted dry
1 cup olive oil, divided
Fleur de sel, to taste
Freshly ground black pepper
24 baguette slices, cut about 3/8 inch thick on the diagonal
1½ cups arugula leaves or watercress sprigs
1/3 cup hazelnuts, toasted and chopped (see note)
Slice mushrooms thinly and place in a large bowl. Add 3/4 cup olive oil, 1 teaspoon fleur de sel and 1/4 teaspoon pepper. Stir until all the mushrooms are coated with oil. Marinate at room temperature 2 hours or up to 5 hours. As the mushrooms marinate, they will soften and release some of their moisture, making the mixture more liquid.
To prepare the bruschettas, arrange a rack at center position and preheat the oven to 350 degrees. Brush the baguette slices lightly on both sides with remaining olive oil, and transfer them to a large foil-lined baking sheet. Bake the bread slices until golden and just crisp, 4 to 5 minutes per side. Remove and leave at room temperature. (The slices can be prepared 3 hours ahead; cover loosely with foil and leave at room temperature.) When ready to serve, place 1 or 2 arugula leaves or watercress sprigs, torn to fit, on top of each bruschetta. Taste the marinated mushrooms and season with additional fleur de sel and pepper, if needed. Using a slotted spoon, top each bruschetta with mushrooms and sprinkle with hazelnuts.
Arrange the bruschettas on a serving tray and serve immediately. Makes 24 bruschettas, or 8 servings.
Note: To toast hazelnuts, spread on a baking sheet and bake in a 350-degree oven until browned and fragrant, 6 to 8 minutes. Remove, and when they are cool enough to handle, place nuts in a kitchen towel and rub together to remove as much of the skins as possible.
I guess you can tell it's Wednesday!