Blender Watercress Sauce

1 cup chopped watercress leaves (may substitute fresh spinach, stemmed)
2 tablespoons olive oil
1/2 cup low-fat plain yogurt
2 cloves crushed garlic
1 teaspoon dried basil
1/4 cup finely chopped flat-leaf parsley
1 lemon (juice only)
1 to 2 tablespoon water (optional)
Freshly ground black pepper
2 tablespoons crumbled feta cheese, plus extra for garnish

Combine the watercress, olive oil, yogurt, garlic, basil, parsley and lemon juice in a blender or food processor. Puree until the mixture is thick, adding
water if necessary to reach the desired consistency. Add salt and pepper to taste. Transfer to a medium bowl and add the feta cheese, stirring to combine.
Serve on or alongside your entree of choice, sprinkling a little extra cheese on top, or cover tightly and refrigerate until ready to use.

Note: Serve with grilled, baked or pan-seared fish or vegetables. You can cook the sauce while they are cooking. It will keep, covered and refrigerated,
for 2 days.

From The Washington Post