Step 1

Thinly slice 1 medium yellow onion and mince 2 garlic cloves. Pick the leaves from 1 sprig fresh parsley and finely chop until you have 1/2 teaspoon.

Step 2

Add 1 pound lean ground beef, 1 teaspoon onion powder, 1 teaspoon garlic powder, and 1/4 teaspoon black pepper to a medium bowl. Use your fingertips to gently combine. Do not overmix.

Step 3

Divide the mixture into 4 (4-ounce) portions. Form each into a patty that’s about 1/2-inch thick and 4 inches wide. Season the patties all over with 1/2 teaspoon of the kosher salt. Place on a plate or baking sheet.

Step 4

Heat 1 tablespoon vegetable or canola oil in a 10-inch or larger cast iron or nonstick skillet over medium heat until shimmering. Working in 2 batches if needed so as not to crowd the pan, add the patties and cook undisturbed until a golden-brown crust forms on the bottom, about 5 minutes. Flip with a thin metal spatula and cook until the second side forms a brown crust, about 5 minutes more. Transfer to a plate.

Step 5

Melt 3 tablespoons unsalted butter in the same skillet over medium heat. Add the onion, 8 ounces sliced cremini mushrooms, and the remaining 1/2 teaspoon kosher salt. Cook, stirring occasionally, until the mushrooms are softened and have released their liquid, about 8 minutes. Add the garlic and cook until fragrant, about 30 seconds.

Step 6

Add 2 tablespoons all-purpose flour and stir to coat the vegetables until the flour is completely absorbed and no dry pockets of flour remain. Cook until golden-brown, 1 to 2 minutes.

Step 7

While stirring constantly, slowly pour in 2 cups beef broth and 1 teaspoon Worcestershire sauce. Bring to a simmer over medium heat, whisking often, 1 to 2 minutes. Continue to cook, whisking often, until thickened enough to coat the back of a spoon, 4 to 5 minutes. Return the hamburger patties to the skillet, nestle into the mushroom mixture, and cook until heated through, about 2 minutes.

Step 8

Divide the hamburger patties between plates, spoon the sauce over top, and garnish with the parsley.