Preheat oven to 350 degrees.
In a small bowl, mix olive oil, herbs de provence, salt, and pepper.
Using about 1/4 mix, cover pork tenderloin and rub around so it is evenly seasoned.
Heat a large, heavy pan, over medium high heat until scorching hot (but not smoking).
Add high-heat oil, and swirl around pan until shimmery.
Add pork to pan and brown on all four sides (about 2 minutes each side if scorching hot).
When pork is browned, remove from pan and place on baking sheet.
Add the brussel sprouts and potatoes to a bowl and toss with the other 3/4 of the olive oil/seasoning mix.
Add the vegetables to the baking sheet around tenderloin.
Bake 20-25 minutes, until an internal temperature of 150-155.
Remove from oven and let rest a minimum of five minutes.
Thinly slice pork and enjoy with brussels and potatoes.