Prepare the Beef:

In a large bowl, combine the thinly sliced beef with salt, cracked black pepper, and onion powder. Toss to coat evenly.

Sprinkle 2 tablespoons of flour over the seasoned beef and toss again to coat.

Sear the Beef:

Heat a non-stick pot over medium-high and add 3-4 tablespoons of olive oil. Once hot, sear half of the beef for about 1-2 minutes per side or until browned. Remove and set aside on a plate. Repeat with the remaining beef.

Caramelize the Onions and Mushrooms:

In the same pot, add more oil if needed. Add sliced onions with a pinch of salt and pepper, cooking until caramelized and golden, about 6 minutes, stirring frequently.

Add the mushrooms and continue to sauté with the onions for another 6 minutes, stirring often.

Make the Stew:

Stir in the dried thyme and minced garlic, cooking until fragrant.

Sprinkle the remaining 2 tablespoons of flour over the mixture, stirring well to combine.

Gradually pour in the beef broth, stirring continuously to prevent lumps.

Reduce the heat to medium-low and simmer for about 10 minutes, uncovered, to thicken the stew slightly and meld the flavors.

Add the Beef Back to the Stew:

Turn off the heat and return the seared beef and any accumulated juices to the pot, stirring to combine. Season with additional salt and pepper if needed.

Spoon the stew into the hollowed-out sourdough bowls. Top each with a slice of provolone cheese.

Place the bread bowls on a foil-lined baking sheet and broil briefly until the cheese is melted and bubbly.

Serve with reserved sourdough bread pieces for dipping.