Recipe courtesy of Frances Keller
Prepare the compound butter by stirring together 2 tablespoons of softened unsalted butter, blue cheese crumbles, chopped thyme and rosemary, and a small pinch of salt and grind of black pepper. Set to the side while preparing the steaks and fries.
Peel the russet potato and slice thin into ¼ thick sticks. Place the fries in a large bowl of water to remove excess surface starch and soak for about 5 minutes before rinsing. Place fries on a paper towel lined plate and dry completely before frying.
When ready to fry, fill a large Dutch oven with 2 to 3 inches of melted duck fat (or your neutral, high-smoke point frying oil) and heat over medium-high heat. The cooking fat/oil should reach a temperature of 350 degrees Fahrenheit prior to frying.
While the fat/oil preheats, season steaks with kosher salt and ground black pepper. Preheat a large cast iron skillet over medium-high heat.
Add olive oil to the now heated skillet and carefully place the steaks in the pan. Allow steaks to sear untouched until golden brown, about 4 minutes. Flip steaks and sear the opposite side for another 3 to 4 minutes. Add the remaining 2 tablespoons of unsalted butter, garlic, and herb sprigs, allowing butter to melt. Spoon the melted butter over the steaks and continue to baste for about 30 to 45 seconds. Remove from heat and tent with foil to allow steaks to rest for about 10 minutes. An instant-read thermometer inserted into the thickest part should read 135 degrees F., for medium-rare doneness.
After flipping steaks, and once fat/oil is ready for frying, add enough potatoes to the pot so that there is a single layer. There should be enough room between the fries so the fat/oil can easily bubble up and nearly cover them. Use tongs to turn the fries as they brown so they fry evenly on all sides until golden brown and crispy for about 7 to 10 minutes. Transfer the browned potatoes to a paper towel lined plate and immediately sprinkle liberally with flaky sea salt. If needing to fry in batches, keep prepared fries in a very low oven until ready to serve. Continue cooking any remaining potatoes in small batches until all of them are done.
When ready to plate, place steaks on two plates and divide the blue cheese compound butter evenly between them. Distribute freshly fried potatoes between the two plates. Serve.
