Reverse searing is the technique used here. It is a popular cooking method for filet mignon among chef's and it's what you'll find in many fine dining restaurants. This easy, straightforward method creates hands down one of the most tender steaks you'll ever eat! You should be able to easily slice through it with a butter knife.
Let steaks rest at room temperature 1 hour uncovered to help take the cold chill off and dry the exterior.
Preheat oven to 250 degrees. Place an oven safe wire cooling rack on a rimmed baking sheet.
After steaks have rested, dab dry with paper towels then season both sides with salt and pepper and gently press salt and pepper over steak.
Transfer steaks to wire rack on baking sheet spacing apart. Insert a oven probe meat thermometer into center of one steak, inserting from the side**.
Bake in preheated oven a few degrees shy of target temperature (testing in center, refer to times below). This should take about 40 - 65 minutes. Time varies based on the doneness you prefer and how thick the steaks are. 2-inch steaks take near the greater time.
Near the end of steaks baking begin preheating a cast iron skillet over moderately high heat. It should preheat 5 - 10 minutes (or longer on electric stoves), until pan smokes. You want the skillet super hot for the next step and pre-heating it is critical to achieve a nicely seared crust in a small amount of time without over-cooking the steak.
Once steaks are done baking add 1 Tbsp light olive oil to preheated skillet, use oven mitts to lift pan and swirl oil around to coat bottom evenly.
Add steaks and sear, and press down on the steaks several places across the top to help achieve a good contact on bottom of steaks (just do this using kitchen tongs from transferring). Sear briefly just until nicely browned on bottom about 45 - 60 seconds.
Turn steaks and sear opposite side until browned about 45 - 60 seconds longer.
Serve warm as is or with a desired sauce (see post above recipe for my favorites).
Notes
*Use steaks that are almost the exact same size (all about 1 1/2 inches thick each or all about 2-inches thick each, and all very close in weight) so they bake evenly and finish at the same time. You can also use a peeled 2 lb beef tenderloin and cut into 4 evenly sized steaks.
*Recipe can be made using 1 - 6 filet mignon's as long as they are nearly the same size. If using more than 4, or if the 4 you have are fairly long then sear in two batches so skillet isn't overcrowded and they brown nicely.
If one of the steaks does happen to be smaller monitor the temp of that one first, then transfer the thermometer to a larger after you've removed the smaller one from the oven.
Steak Doneness Temperatures
Rare: 120- 125 degreesMedium-rare: 130 - 135Medium: 140 - 145 Medium-well: 150 - 155Well: 160 - 165 (not recommend highly overcooked!)Filet mignon is best cooked just to medium or medium-rare, rare is not recommended for food safety. Note that USDA recommends heating to 145 degrees.