Preheat oven to 375 degrees. Wash beets thoroughly. Set each beet on a square of foil large enough to enclose it. Break star anise in half and place a piece on each square (or if using anise or fennel, divide among packets). Crimp each packet tightly shut.

Set beets in roasting pan. Bake until tender when pierced through with knife tip or cake tester, about 40 to 60 minutes.

Meanwhile, rinse greens in several changes of water

Cool beets or not, as convenient. Keeping them wrapped up, gently squish each beet, sliding the skin back and forth so that it loosens. Open foil and, still holding beet with it, slip off skin and stem. Discard with spices. Halve beets.

Set greens on a rack in a steamer over boiling water. Cover and cook until tender, about 5 minutes. Meanwhile, heat beets in a pan with butter.

Toss greens with lemon juice. Arrange in a ring on serving dish. Nest beets in center.