Yield: 12 mushroom appetizers
12 medium-sized mushroom caps
1 tablespoon olive oil
1 tablespoon unsalted butter
½ cup finely chopped yellow onions
2 tablespoons coarsely chopped walnuts
1 clove garlic, minced
5 ounces spinach, thoroughly defrosted and squeezed dry
1 ounce feta cheese
1 ounce Gruyere cheese, crumbled
2 tablespoons fresh dill
Salt and freshly ground pepper, to taste
Preheat oven to 400 degrees F
Remove stems from mushrooms and wipe the mushroom caps with a damp cloth or paper towel. Set aside. In a small skillet, heat olive oil and butter and add the onions and sauté until the onions are tender and translucent, approximately 10-15 minutes. Add walnuts and garlic and sauté for an additional minute. Add spinach and cook for another 5 minutes, stirring constantly. Remove from heat and cool slightly. Stir in cheeses, dill and seasonings.
Arrange the mushrooms, cavity side up in a baking dish. Divide the spinach and walnut mixture evenly among the mushroom caps. Bake in the oven for approximately 8-10 minutes until the filling is browned and the mushrooms are thoroughly heated. Remove from oven and serve immediately.
Source: The Silver Palate – Rosso & Lukins – 1979