Place chicken breasts between sheets of plastic wrap. Use a meat mallet to pound them thin. Aim for about $1/4$ inch thickness. This ensures the chicken cooks evenly and fast. Season both sides with salt and pepper.

Mix flour and garlic powder in a shallow dish. Lightly dredge each chicken breast in the flour. Shake off the excess flour gently. A thin coating creates a beautiful golden crust when frying.

Boil water in a medium saucepan. Add asparagus for 2 to 3 minutes. They should be bright green and crisp-tender. Drain and place in ice water. This stops the cooking and keeps them green.

Heat olive oil in a large skillet. Add 1 tablespoon of butter. Cook chicken for 4 minutes per side. It should be golden and cooked through. Remove the chicken and set it aside on a plate.

In the same skillet, add the rest of the butter. Toss in your sliced mushrooms. Cook until they are brown and tender. This takes about 5 minutes. The mushrooms soak up the tasty chicken bits.

Pour the Madeira wine into the skillet. Scrape the bottom to release flavor. Add the beef stock. Boil until the liquid reduces by half. The sauce will become thick, dark, and very glossy.

Place the chicken back into the skillet. Lay the asparagus spears over the chicken breasts. Top each one with plenty of mozzarella cheese. Use a lid to cover the pan for a few minutes.

Keep the lid on until the cheese is gooey and melted. If your pan is oven-safe, you can broil it. Broiling makes the cheese bubbly and brown. Serve the chicken immediately while it is hot.