we love pork tenderloin. when it summertime out, we grill it. First we marinate the PT in an easy marinate of 1/3 soy sauce, 1/3 c honey and 1/3 c orange marmalade. I mix the marinade ingredients together and microwave until bubbly (about 1 minute). Pour over PT in a large ziploc and marinate for 5 or more hours. Grill until thickest section reaches 145, turning often. Remove from heat, tent with foil and let rest 5 minutes before slicing.
In the winter months, I make PT in the oven. First I heat my own to 400, then I smother the PT in dijon and brown on all sides on medium high heat with about 2-3 T of olive oil. I use a dutch oven. Then I stick it in the oven and continue cooking until it reaches 145, about 20 minutes. Remove from the heat and tent with foil. Return the dutch oven to the stovetop and pour in 1/4 C apple cidar vinegar, 2 -3 T of dijon, a drizzle of maple syrup and some fresh sage or herbs de provence. Let it come to a boil, it will thicken up. Slice the PT and drizzle the sauce over top.
PT is great but don't overcook it, it will be like shoe leather if you do. It is a lovely piece of meat if you prepare it properly.