You can of course use another steak such as a rib eye or even a sirloin if you do not wish to put out the money for filet. You can also use blue cheese and dried thyme. You don't have to use a food processor either. Life did exist prior to their invention.You do need the porcini mushrooms and they are usually available in most grocers in little plastic bags. I made this the other night using a sirloin and slicing it and serving the sauce on top. It was wonderful. Very rich.
Filet:
1 (4 to 6-ounce) petite filet of beef
Pinch salt
Pinch freshly ground black pepper
3 tablespoons olive oil
Gorgonzola and Porcini Mushroom Sauce:
3 tablespoons olive oil
1/4-pound (about 1 cup) dried porcini mushrooms, soaked and strained
1 shallot, sliced (about 2 tablespoons)
1 teaspoon chopped fresh thyme leaves
1/4 cup dry white wine
1/4 teaspoon salt
1/4 teaspoon freshly ground black pepper
3 ounces (about 3 tablespoons) Gorgonzola
1/2 cup mayonnaise
1 teaspoon Dijon mustard
For the beef:
Preheat the oven to 350 degrees F.
Sprinkle both sides of the beef with salt and pepper. Heat the olive oil in an oven-safe medium skillet over high heat. When the oil is hot, carefully place the filet in the pan. Cook until browned on both sides, about 3 to 4 minutes a side. Transfer the steak to the oven and bake until a meat thermometer reads 130 degrees F. for medium-rare, about 5 to 6 minutes. Remove the beef from the oven and let rest for 5 minutes.
For the sauce:
Heat the olive oil in a medium skillet over medium heat. Add the mushrooms and the shallots and cook until golden brown and tender, about 5 minutes. Add the thyme, white wine, salt, and pepper and continue to cook until all of the liquid has evaporated, about 5 more minutes.
Meanwhile, put the Gorgonzola, mayonnaise, and mustard in a food processor and combine until smooth. Transfer the Gorgonzola mixture to the skillet with mushrooms and shallots. Gently stir the cheese mixture into the mushroom mixture.
Slice the beef and serve topped with a dollop of the cheese sauce. Reserve leftover sauce for another use.