Sweet and Sour Pork Tenderloin

Place the mustard in a bowl and add the orange juice, honey, and beer. Mix with a whisk and set aside.

Cut the tenderloin into a 'triptych' shape: make a cut from one end to the center without cutting all the way through, and open it like a book. Repeat the process from the center, opening it in the opposite direction. Season with salt.

Peel the apple, remove the core, and slice it thinly. Place the apple slices and pitted prunes on top of the meat, then roll it up tightly into a cylinder. Tie the meat with kitchen twine, wrapping it securely to hold its shape. Place it in an oven-safe dish.

Drizzle a bit of olive oil over the meat, season with salt, and pour the mustard sauce over the tenderloin. Bake at 180°C (350°F) for 35-40 minutes, basting the meat with the sauce every 5 minutes. Keep warm once done.

Heat the meat's cooking juices in a saucepan. Chop the spinach, and when the juices start to boil, add the spinach and cook for about 2 minutes. Stir in the diluted cornstarch and mix until the sauce thickens.

Remove the kitchen twine from the pork tenderloin and slice it. Serve with the spinach, drizzle the sauce over the top, and enjoy!