Preheat the oven to 400˚F (unless you plan to make this in advance and refrigerate it - then you will preheat the oven later).
Combine the minced garlic, tarragon, salt, pepper, fennel, capers and olive oil until the mixture forms a paste. I like to chop everything but the oil together on a cutting board, then mix it all in a small bowl. Press this mixture onto the tenderloin.
Wrap bacon around the herbed tenderloin, doing your best to keep the paste inside the bacon wrap. At this point you can cover and refrigerate, up to several hours, or bake right away.
If you have refrigerated the pork tenderloin, remove it from the refrigerator and allow to sit at room temperature for about 30 minutes. (About 20 minutes into that, preheat the oven).
Transfer to the oven and roast 15-20 minutes (depending on the thickness of the tenderloin) until a meat thermometer inserted into the thickest part reads 130 degrees F.
Reduce the oven temperature to 350 degrees F.
Remove pan from the oven. As quickly as possible, spoon off any excess bacon grease and place asparagus and tomatoes in the baking dish. Sprinkle the vegetables with the salt and pepper. Drizzle the balsamic vinegar over the vegetables.
Return the baking dish to the oven and cook for 25-30 minutes more until the meat thermometer registers 155 degrees F and the tomatoes are starting to puff up.
Turn on broiler to high, and broil for 5 minutes to crisp the bacon.
Remove baking dish from the oven and let rest for 5 minutes before slicing.
Cut the tenderloin into ¾" slices and spoon the pan drippings over the meat. Serve with tomatoes and asparagus.
Great with roasted sweet potatoes, small roasted new potatoes or a fresh salad.