Make the sauce: combine boiling water and mushrooms in a bowl; cover and let stand for 10 minutes or until tender.
Drain, rinse and drain mushrooms; chop mushrooms.
Heat oil in a medium pan over med-high heat; add in mushrooms, onion, and shallots; stir/saute for 3 minutes or until onions are tender.
Decrease heat to medium; add in broth, wine, thyme, and bay leaf; bring to a simmer, cook 6 minutes.
Discard bay leaf.
Combine 2 tablespoons water and cornstarch in a small bowl; stir with a whisk.
Add cornstarch mixture to pan; bring to a boil; cook 1 minute, stir constantly.
Remove pan from heatt, stir in salt and pepper; keep warm.
Preheat oven to 400°.
Prepare beef: heat a large nonstick skillet over med-high heat; sprinkle beef with salt and pepper.
Coat skillet with cooking spray; add beef to pan; cook 1 minute per side or until browned. Wrap handle of pan w/ foil, place pan in oven; bake at 400° for 5 minutes or until desired degree of doneness.
Place beef on a platter, let stand 5 minutes before serving; serve with sauce.