Souffled Twice-Baked Potatoes with Kale or Spinach

1. Heat oven to 375°F. Scrub potatoes; prick each one with a sharp fork in 2 to 3 places. Bake until fully tender when pierced with a fork, about 1 1/4 hours.

2. Cut a 1/2-inch slice lengthwise from each potato. Scoop out flesh from top slices and from inside the potatoes, to make shells with 1/4-inch thick “walls.”  Pass the still-hot potato flesh through a potato ricer. (You can also mash the potatoes with electric beaters, but don’t overdo it, or the spuds will become gluey). Use a rubber spatula to fold butter and hot milk into potatoes.

3. Separate the eggs, placing yolks in a small bowl and whites in a clean, medium bowl. Beat egg yolks; fold yolks, kale or spinach, chives, salt and pepper into potatoes. Use clean electric beaters or a large whisk to whip egg whites until firm, but not stiff. Fold a quarter of them into potato mixture, then gently fold in the rest. 

4. Heap mixture into potato shells. Place on ungreased baking pan; bake until potato mixture is brown-tipped and heated through, about 25 minutes.