In a large bowl, mix together all ingredients for the steaks - except for the olive oil. Combine well. 

Divide the mixture into 4 sections and shape into patties about 3/4" thick.

Warm the olive oil over medium-high heat in a large nonstick skillet. Add the steaks to the skillet and cook about 3 minutes per side until they develop a golden crust. They will not be fully cooked.

Transfer to a plate. 

Reduce the heat to medium and add butter to the skillet. Do not clean the skillet first. 

Once butter is melted, add flour and whisk until smooth. 

Reduce heat to medium-low and pour in beef stock. Whisk well. Add ketchup, Worcestershire sauce, and onion powder. Whisk to combine.

Add mushrooms to sauce and simmer for 5 minutes. Season with salt and pepper. 

Add cooked steaks back to the sauce. Cover with the gravy and cook for 10 more minutes until steaks are fully cooked through.

Serve over mashed potatoes with sauce drizzled on top.