A Flattened Beef 'Roast'
Classic Fillet Mignon . . .
From a beef Tenderloin, cut a piece about 4 - 6 inches in length.
Stand the piece on your board and press it down to about two thirds (maybe even half) of its original height.
Proceed with your Fillet Mignon.
Most available Fillet Mignon is cut to the end-cooking thickness, which won't yield the same mouth feel and flavour experiences that a classic preparation will give the dinner. Some of the benefits of roasts are advantages of thickness, mass, retention of moisture, retardation of the speed of heat penetration . . .
Other than this, I think a flattened Beef Roast might be counter-productive.