2 pounds beef top round
¾ teaspoon Kosher or Sea Salt, plus extra
¾ teaspoon Cracked black pepper, plus extra
1½ teaspoons granulated onion, divided
5 tablespoons all-purpose flour, divided
3 tablespoons canola, vegetable, or other neutral oil
4 tablespoons butter, divided
2 onions, trimmed of both ends, halved, peeled, and cut into thin half moons
8-10 ounces white or baby bella (cremini) mushrooms, sliced (*See Notes)
1 teaspoon dried thyme
3 cloves garlic, peeled and minced or pressed
4 cups beef stock
4 sourdough bread bowls, centers cut out to within ¾-inch of the bottom and sides and reserved for the crouton
4 slices provolone cheese