Set sous vide machine to 60C/140F.
Put the pork tenderloin in a freezer bag and remove the air through a vacuum sealer or the displacement method. Drop tenderloin in the bath for 2 hours.
Remove bag from bath. Take pork out of the bag, pat dry and lightly season with salt and pepper or your favorite seasoning to taste.
Heat a large skillet on high and add oil. Sear for 60 seconds on each side. If you have a grill, preheat on high and sear for 60 seconds on both sides. Remove from pan or grill and place on plate to rest. Slice the tenderloin and serve with the peach mustard sauce (directions below) and enjoy!
Combine peaches, ketchup, mustard, brown sugar, salt and pepper in a food processor or blender. Blend until sauce is smooth.