6 filets mignon, 6 oz each and about 1 3/4" thick
1 T unsalted butter
1 T vegetable oil
Two 5.2 oz cakes peppercorn Boursin cheese, slightly softened at room temperature
One 1lb. pkg. phyllo dough, thawed in refrigerator overnight
1/2 c. butter, melted (more if needed)
1/4 c. thinly sliced chives
1 lb. fresh white button mushrooms, cleaned
2 medium shallots
1 clove garlic, cut in half
1 T. olive oil
1/4 c. chopped fresh parsley
kosher salt and fresh ground black pepper
1. Season the filets generously on all sides with salt. Heat the butter and oil in a 10" skillet over medium high heat until very hot and sizzling.
2. Put three of the filets in the pan ad Season on both sides. Transfer to a place lined with paper towels. Repeat with remaining filets. Cover and refrigerate for at least 1 hour.
3. Mash Boursin with a fork in a small bowl until spreadable. Remove at least 24 sheets of phyllo from the package and cut into 10" squares. Cover them with plastic wrap and a damp dishtowel while you work, to keep them form drying out. Lay a single phyllo sheet on clean, dry surface. With a pastry brush, lightly paint an even coat of melted butter over the entire surface of the square. Sprinkle with about 1/2 t. chives. Set a second sheet at a 90 º angle over the first. Brush butter over it as well and sprinkle with another 1/2 t. chives.
4. Make four layers, omitting the chives from the last layer, with the corners of the phyllo pointing in different directions, star-like. Blot one filet dry with paper towel, set it in the center of the star, and sprinkle it with salt. Spread about 2T. Boursin on the filet and top that with 2 generous tablespoons of mushroom filling.
5. Pick a starting point and work your way around the filet fathering the edges of the phyllo star together, beggar's purse style. Lightly pinch together the gathered phyllo close to the surface of the meat to hold it in place. Pull the corners open slightly as if making a paper flower. Brush the whole exposed surface lightly with more butter, being sure that the boom is buttered as well. Transfer to a heavy baking sheet. Repeat on other filets. Refrigerate filets uncovered on the baking sheet until ready to bake, up to 8 hours.
6. TO BAKE
Take the croustades out of the refrigerator about 20 minutes before you're ready to bake them. Position an oven rack in the lower third of the oven and heat the oven to 400º. Bake the crousades, rotating the baking sheet after 10 minutes to ensure even browning, until an instant-reading thermometer inserted through the side of each packet and into the center of the filet reads 130º for RARE , 17 TO 22 MINUTES. Serve immediately.
Trim mushrooms stems close to the caps. Put the mushrooms, shallots and garlic in a food processor and pulse until finely chopped but not pureed; scrape the bowl as needed. Transfer the chopped mushrooms to the center of a clean dishtowel. Gather up the sides of the towel and twist, keepint the mushrooms well contraine in the cloth, bonbon style. With one hand, hold the ball of mushrooms over the sink, iwth the otehr hand, twist the gathered cloth, squeezing out as much liquid as possible.
Heat the butter and oil in a 10" skillet over medium heat. Ad the mushrooms, cover and cook, stirring occasionally, until the mushrooms are very soft and fragrant, 3 to 5 minutes. Don't let them brown.Uncover and cookk until pan is mostly dry, 2 to 3 minutes. Add the parsley; season with 1/2 t. salt and pepper to taste. The filling can be refrigerated for up to a week or frozen for up to two weeks. If frozen, thaws overnight in the refrigerator and, if necessary, cook gently in a uncovered skillet to evaporate any juices that may have developed.