Combine milk and eggs in a bowl. Weigh or lightly spoon 5 ounces flour into a dry measuring cup; level with a knife. Add flour and 1/2 teaspoon salt to milk mixture, stirring well; let stand 30 minutes. Place popover tin in oven for 5 minutes. Remove tin from oven; lightly coat popover cups with cooking spray. Spoon 1/4 cup batter into each cup, and sprinkle with cheese. Bake at 400° for 35 minutes or until puffed and golden.
Place porcini mushrooms in a bowl, and cover with 2 cups boiling water. Let stand 15 minutes. Drain through a sieve over a bowl, reserving mushrooms and soaking liquid. Heat a large saucepan over medium-high heat. Add 1 1/2 teaspoons oil to pan; swirl to coat. Add shallots to pan; sauté 1 minute, stirring frequently. Add cremini mushrooms to pan; sauté for 2 minutes or until almost tender. Add garlic to pan; sauté 30 seconds, stirring constantly. Stir in porcini, 1/4 teaspoon salt, and 1/4 teaspoon pepper; sauté 1 minute, stirring frequently. Add wine to pan; bring to a boil. Cook until liquid almost evaporates (about 3 minutes). Sprinkle 2 tablespoons flour over mushroom mixture; cook for 1 minute, stirring frequently. Gradually add the reserved mushroom soaking liquid, stirring constantly; bring to a simmer. Cook 2 minutes or until slightly thick, stirring frequently. Stir in herbs.
Heat a large skillet over medium-high heat. Add 1 tablespoon oil. Sprinkle beef with 1 teaspoon salt and 1/2 teaspoon pepper. Add beef to pan; sauté 4 minutes on each side or until desired degree of doneness. Remove from pan; let stand 10 minutes.
Wine note: Beef Filets with Mushroom Sauce and Parmesan Popovers pairs well with 2007 Bodeaga Catena Zapata Malbec from Mendoza, Argentina ($20). It has a smooth tobacco aroma that opens into deep waves of vanilla and cassisfilled out by roasted plums and caramelized grapefruit. --Alexander Spacher