In a shallow roasting pan, place pork tenderloin onto a rack.
Roast at 425 degrees farenheit for 25-30 minutes in the middle oven rack.
While pork is roasting, make the sauce.
Make the Blackberry Bacon Sauce
In a large saucepan, heat the butter over medium-high heat until it's just melted. Add bacon slices. Stir and cook bacon until slightly crispy, about 5 minutes.
Add mushrooms and garlic to the pan. Bring heat down to medium.
Stir until ingredients are well mixed. Slowly add balsamic vinegar and cook for 2 minutes.
Add blackberries, bring heat to low. Simmer for 5-7 minutes.
Keep sauce on the stovetop on low heat until the pork is done. Plate and serve immediately.