Season your steak pieces with salt and pepper to taste.
In a large deep skillet, heat your oil on high. Once hot, add in your steak, spread slightly apart (depending on the size of your pan, you may have to work in 2 batches). Cook the meat until browned on all sides. Remove from the pan, cover to keep warm and wipe down the pan.
Next, melt the butter and add in the onion and mushrooms. Season with salt and pepper to taste. Cook until tender - 4 minutes. Stir in the garlic until fragrant - 30 seconds.
Sprinkle everything in the pan with the flour and stir until all is coated, about 1 minute. Slowly add in broth, stirring constantly, until smooth. Once the sauce starts to boil, reduce the heat to low and allow to simmer for 2 minutes. Mix in the Worcestershire and soy sauce once the sauce has thickened.
Introduce the steak back into the pan and coat everything. Cook for another few minutes for the meat to warm back up. Top with parsley and serve.