Preheat oven to 400°F (200°C). Place tenderloin on a baking sheet and bake for about 18-25 minutes or until the internal temperature reaches 160°F (72°C). Set aside to rest.

To make the sauce: In a small saucepan or skillet, heat the broth over medium-high heat. Bring it to a simmer and cook for about 2 minutes until it reduces a little.

Reduce heat to low and stir in sour cream, mustard, and half of the dill. Continue cooking another 2 minutes.

Turn off heat and add butter with a pinch of salt/pepper. Stir until butter has melted into the sauce.

Slice pork and spoon sauce over top. Garnish with remaining dill and serve.