Step 1

Crush all sea salt and spices together. Wipe duck with paper towel and pat dry, then rub spice mixture over duck. Let sit for 20 min at room temperature.

Step 2

Put duck in a slow cooker. Add finely chopped onion and garlic, then pour butter over meat. Cover and cook on low for 6 hours.

Step 3

Strain out cooking juices. Cool quickly so fat solidifies and broth separates. Remove fat with a spoon and save broth for sauce.

Step 4

Bring about 1/2 cup broth to a pan and simmer on low, stir in balsamic vinegar, mustard and tomato paste. Add sour cream.

Step 5

Garnish duck legs with sauce and sprinkle with spring mix salad and serve.