WP, including an amusing riff on how this dish was incredibly popular during the latter part of the 20th century, even served at "posh" affairs, but then was rebranded as mundane and disappeared. It sounds delicious, especially when served over a puff-pastry cup (which can be found at some supermarkets), although this high-end recipe is somewhat a lot of work.
Ingredients
1 ounce dried porcini mushrooms
Hot water
4 tablespoons (1/2 stick) unsalted butter
2 medium shallots, minced (about 1/4 cup)
8 ounces fresh mushrooms, sliced
2 medium cloves garlic, minced
1/2 teaspoon fine salt
3 tablespoons all-purpose flour
2 cups low-sodium chicken broth
1 cup whole milk
2 whole chicken breasts, poached (see NOTES), cooled, then skinned, deboned and cut into 1/2-inch dice (about 4 cups; may substitute 4 cups diced cooked chicken)
1 cup frozen peas, defrosted
2 large egg yolks
1/3 cup heavy cream
1/4 teaspoon freshly ground black pepper, plus more to taste
1 tablespoon dry sherry or amontillado sherry
1 tablespoon minced fresh tarragon
1 tablespoon minced fresh flat-leaf parsley
Instructions
1. Place the dried porcini mushrooms in a medium bowl, add enough hot water to cover and let soak for 20 minutes. Remove the reconstituted mushrooms from the water and squeeze them over the bowl.
2. Line a strainer with a few layers of cheesecloth, then strain the mushroom soaking water, reserving 1/2 cup. Rinse the reconstituted mushrooms.
3. In a large saucepan over medium heat, melt the butter. Add the shallots and cook, stirring, until softened, about 3 minutes. Add the fresh mushrooms and garlic and cook, stirring, until the mushrooms have softened, about 5 minutes.
4. Add the salt and the reconstituted mushrooms and cook, stirring, for 1 to 2 minutes, then add the flour and cook, stirring, until combined, about 1 minute. Whisk in the broth, the reserved mushroom soaking liquid and milk. Bring to a boil, stirring constantly, then reduce the heat to low and cook, stirring, until smooth and thick, 10 to 15 minutes; there should be no lingering raw flour taste.
5. Add the chicken and peas, stir to combine and just heat through.
6. Shortly before serving, in a small bowl, beat the egg yolks with the cream until combined. Transfer 1/2 cup of the sauce from the saucepan into the mixture and quickly whisk them together; when it is incorporated, add the egg mixture to the saucepan. Cook, being careful not to let the sauce get too hot or start to simmer (or the eggs might curdle), about 5 minutes.
7. Add the 1/4 teaspoon of pepper, sherry, tarragon and parsley. Taste, and adjust seasonings.