Preheat oven to 425° + place a sheet pan in oven; heat 1 tbsp oil in skillet over med-high; pat pork dry, season with salt/pep + sear undisturbed 2-3 min on each side; carefully remove sheet pan from oven + place pork on sheet pan; roast pork 25-30 min until cooked through, no pink remains + internal temp is 145°; rest pork 5 min; slice against grain + divide ½ of pork onto plates (save leftovers for lunch tomorrow)

Slice any large chopped celery in half, pat dry + mix with 1 tbsp oil + salt/pep; add to one half of a sheet pan

Mix half the potatoes with 1 tbsp oil, salt/pep + fave spices, then spread on the sheet pan next to chopped celery; roast veggies 20-25 min til tender, flipping chopped celery over half way through the cook time

Divide all to plates + drizzle horseradish onto pork