Prepare the steaks first and get them marinating. Do not trim the steaks of fat before grilling; the fat will keep the moisture in. Place the steaks onto a tray and drizzle the olive oil and vinegar over each steak, massaging them into the meat.
Next, season generously with coarse sea salt, followed by a sprinkling of the herb de provence blend and black pepper. Place the steaks on a wire rack over the tray; this will help dry the steaks and remove moisture. Allow the steaks to marinate for a minimum of 4 hours; best if done overnight.
Baby Potato Side Dish:
Prepare the potatoes last, before grilling the steaks. Place whole baby potatoes into a large pot filled with salted water and bring to a boil. Cook for about 15 minutes, until the potatoes are fork tender, then drain. Cut larger potatoes in half at this time.
Preheat a large frying pan over medium heat and add the butter and oil and the cooked potatoes. Season the potatoes generously with salt, then fry the potatoes over medium heat until golden brown. Toss the potatoes every 3 to 4 minutes, cooking for about 20 minutes total. Once the potatoes are golden, season with the remaining spices: paprika, herb de provence, garlic powder and black pepper.
Grilling the Steaks:
Remove the steaks from the refrigerator at least 1 hour prior to grilling, to allow the meat to warm up a bit.
For grilling the steaks, preheat the grill to 600F (high heat) first. Place the steaks onto the hot grill, spacing at least 6 inches apart. Grill the steaks with the grill lid open; grill for 7 to 8 minutes per side, rotating 45 degrees at the halfway point to achieve even grill marks. After 7 to 8 minutes, turn the steaks and repeat for the other side.
For a medium to medium-rare doneness, allow the internal temp to reach 130F.
This timing is for 1-inch thick steaks, medium-rare doneness; adjust accordingly for thicker or thinner steaks. For thinner steaks, grill at least 2 minutes less; for thicker steaks, grill at least 2 minute more per side and close the grill lid. For more well-done steaks, also close the lid.
Allow the steaks to rest for at least 5 to 10 minutes before using a sharp knife to trim off the bone and any excess fat off the sides. Slice the steak into thick slices and serve with the baby potatoes on the side, and dress with chimichurri sauce and steak sauce.