Notes: Add potatoes to oven for the last hour that your St. Patrick's Day corned beef bakes. If the beef is done before the potatoes, let it continue cooking until potatoes are ready. If making green sauce up to 1 day ahead, cover and chill.
12 to 16 round red thin-skinned potatoes (2 1/2 in. wide; 2 to 2 1/2 lb. total)
2 tablespoons lemon juice
1/4 cup chopped parsley
3/4 cup lightly packed rinsed and drained watercress sprigs
1/4 teaspoon dried tarragon
3/4 cup sour cream (or half sour cream and half plain yogurt)
How to Make It
Scrub potatoes and pierce each with a fork.
Set potatoes directly on the rack in a 325° oven and bake until soft when pressed, 1 to 1 1/4 hours (about 45 minutes in a convection oven).
Meanwhile, in a blender or food processor, combine lemon juice, parsley, watercress, tarragon, and sour cream. Whirl until mixture is smoothly puréed, scraping container sides as required.
Cut a slit across the top of each potato and pinch sides to pop open top. Set potatoes on a platter and spoon a little of the green sauce into each. Serve with remaining sauce and salt to add to taste.