- 1 beef tenderloin (2 lbs, tied)
- 2 teaspoons olive oil
- 3 teaspoons butter (divided)
- 1 1/2 teaspoons sea salt (divided)
- 1/2 teaspoon black pepper (freshly ground)
- 2 tablespoons mustard (country)
- 6 thyme sprigs
- 2 large potatoes (such as russet, Yukon Gold or red, ends trimmed)
- Preheat oven to 425° F
- Heat olive oil in heavy skillet over medium-high heat. Season tenderloin with salt and pepper. When skillet is hot, sear on all sides until nice crust forms. Once seared on all sides, turn off heat and add 2 teaspoons butter to skillet, turning meat to coat. Let rest while preparing potatoes.
- Attach Vegetable Sheet Cutter Attachment to KitchenAid® Stand Mixer. Insert food holder into center of one end of potato, secure onto attachment. Insert food skewer through potato, up to first mark. Attach Thick Blade to attachment. Position bowl under blade to catch potatoes. Turn Stand Mixer to Speed 2 and position blade against potato to process. Repeat with remaining potatoes.
- Transfer potato sheets to cutting board lined with paper towel. Cut sheets into 3-4-inch lengths. Remove excess moisture with paper towel.
- Rub all sides of meat with mustard and center on baking pan. Shingle potatoes over meat, making sure to overlap slices. Tuck thyme sprigs between meat and potato slices. Roast 15 minutes.
- Remove from oven and brush potatoes with remaining butter that has been melted. Sprinkle with 1/2 teaspoon sea salt and return to oven. Continue roasting, 20-25 minutes, until internal temperature reaches 120° F, for medium rare.
- Remove from oven and let rest 15 minutes before slicing.