Dry pork loin on paper towel, then season both sides with salt and pepper
In a large skillet or saute pan on high heat, add oil and sear pork loin on both sides - 2 to 3 minutes on each side.
Add maple syrup, vinegar, honey, stock and mustard. Lower heat to medium low and cook 6-12 minutes. Flip loin halfway through.
As glaze reduces, add butter and spoon glaze over pork loin until internal temperature reaches 140 degrees. Remove from heat.