Preheat oven to 425ºF.

Pat the pork tenderloin dry and season all over with salt and pepper.

Heat 1 tablespoon extra virgin olive oil in an oven-proof skillet over medium-high heat. Once hot, add the pork tenderloin and cook for 4–5 minutes per side until browned all over. Transfer to a plate.

Heat another teaspoon or two of olive oil in the skillet over medium heat. Add the leeks and season with salt and pepper. Cook for 5 minutes, stirring often.

Add the garlic and cook for 1 minute until fragrant.

Add the chopped cabbage to the leeks and season with salt, pepper, and a pinch of crushed red pepper. Cook for 5–7 minutes.

As the cabbage cooks, whisk together the whole grain mustard, honey, Dijon mustard, and water in a bowl until smooth.

Pour the sauce into the skillet and bring to a boil. Taste and add salt and pepper if needed.

Place the pork tenderloin on top and transfer to the oven for about 20 minutes or until it reaches 140ºF at the thickest part of the tenderloin.

Remove the skillet from the oven and transfer the tenderloin to a cutting board to rest for 5 minutes.

Return the pot of drained potatoes to the stovetop over low heat. Add the reserved potato water and mash with potato masher until mostly smooth. Add the milk, garlic powder, paprika, white pepper, and a big pinch of salt. Mash until the potatoes reach your desired consistency. Taste and season. Set aside and keep warm.

Slice the pork tenderloin into thin medallions. Spoon the mashed potatoes onto opposite sides of a serving platter and pile the cabbage on top. Arrange the sliced tenderloin in the middle and garnish with fresh dill. Enjoy!