Pork Medallions with Mustard-Chive Sauce

Ingredients

• 2 tablespoons butter divided ()
• 0.5 cup crème fraîche sour
• 0.5 cup wine dry white
• 2 tablespoons chives fresh chopped
• 2 tablespoons parsley fresh chopped
• 1 tablespoon tarragon fresh chopped
• 2  garlic clove minced
• 2 cups leek white green chopped ( and pale parts only; 2 medium)
• 1 cup chicken broth 
• 2 tablespoons olive oil divided
• 2 pound pork tenderloin 
• 3 tablespoons coarse mustard whole

Equipment

• frying pan
• whisk

Directions

1. Melt 1 tablespoon butter with 1 tablespoon oil in large skillet over medium-high heat.
2. Add leeks and cook until beginning to turn golden, stirring frequently, about 5 minutes. Stir in broth, wine, and garlic. Boil until mixture is reduced to 1 2/3 cups, about 4 minutes.
3. Whisk in crème fraîche and mustard; set aside. (Sauce can be made 2 hours ahead.
4. Let stand at room temperature.) Melt 1 tablespoon butter with 1 tablespoon oil in another large skillet over medium-high heat.
5. Sprinkle pork with salt and pepper. Sauté until browned and cooked, about 5 minutes per side.
6. Transfer pork to platter.
7. Add sauce to skillet; simmer sauce over medium heat until slightly thickened, scraping up any browned bits, about 2 minutes. Stir in chopped chives and tarragon. Season with salt and pepper.
8. Return pork to skillet. Cook over medium heat just until rewarmed, stirring frequently, about 1 minute.
9. Transfer to platter, sprinkle with parsley, and serve.