Preheat and prep: Heat your oven to 425°F (220°C).
Pat the pork tenderloins dry with paper towels. Dry meat browns better.
Mix the seasoning: In a small bowl, combine ranch seasoning, smoked paprika, garlic powder, onion powder, black pepper, and salt. If using Dijon, rub it directly on the pork before the dry seasoning.
Season generously: Drizzle 1 tablespoon of olive oil over the pork and rub it in.
Sprinkle the seasoning blend all over, pressing to adhere. Coat every side.
Sear for crust: Heat a large oven-safe skillet over medium-high. Add the remaining 1 tablespoon of olive oil.
Sear the pork 1–2 minutes per side until lightly browned. Don’t skip this—searing adds flavor.
Optional butter baste: Add the butter to the skillet. Once melted, tilt the pan and spoon the butter over the pork a few times for extra richness.
Roast quickly: Transfer the skillet to the oven.
Roast 10–15 minutes, depending on thickness, until the thickest part reaches 140–145°F (60–63°C) on an instant-read thermometer.
Rest before slicing: Move the pork to a cutting board and tent loosely with foil. Rest 5–8 minutes. The temperature will rise a few degrees, and juices will redistribute.
Slice and serve: Slice into 1/2-inch medallions.
Sprinkle with chopped parsley or chives. Serve with lemon wedges if you like a fresh pop of acidity.