Decadent pork tenderloin and sweet potatoes are balanced nicely by the sour green apple flavor of the rhubarb. If you're not used to cooking with rhubarb, this recipe makes a good introduction. 

Preparation

Wash and trim any leaves from the rhubarb stalks. Julienne 1 stalk of rhubarb and place in a container. Split the remaining stalks in half lengthwise and cut into 2-inch lengths.

Combine the vinegar, peppercorns, mustard seeds, and sugar in a small sauce pot, then bring to a boil. Pour the hot pickling liquid over the julienned rhubarb and cover. Let cool to room temperature. Once cooled, toss the pickled rhubarb with parsley and set aside.

Preheat oven to 400°F.

In a small sauce pot with a lid, add the sweet potato, heavy cream, and milk. Bring to a gentle simmer, cover, and cook on low until the sweet potato is very tender. When tender, remove sweet potato from the liquid and pass through a food mill. Hold warm until ready to serve.

While sweet potato is cooking, trim any excess silver skin and fat from the pork tenderloin. Season with salt, pepper, and ground fennel. Heat an oven-safe sauté pan to medium-high heat. Add the vegetable oil and sear the tenderloin on all sides until well-browned. Once browned, place the pan into the oven and cook for 8–12 minutes, or until pork reaches an internal temperature of 145°F. Turn the tenderloin over halfway through for even cooking.

When the pork has reached the desired degree of doneness, remove from the pan and allow to rest for 7–10 minutes before carving.

Using the pan the pork was cooked in, add the apples and remaining rhubarb and quickly sear over medium heat until just browned. When cooked, remove apples and rhubarb from the pan and transfer to a serving plate. Set aside.

Using the same pan, add the chicken stock and bring to a boil. Reduce by half, then whisk in the butter. Slice the pork tenderloin into medallions and serve on a bed of apples and roasted rhubarb beside the mashed sweet potato. Top with the pan sauce and finish with the pickled rhubarb.