Step 1

Arrange oven racks in the center and upper third positions. Preheat the oven to 425°F.

Step 2

Put the shredded cabbage on a large baking sheet. Add a drizzle of extra-virgin olive oil, and a sprinkling of kosher salt and freshly-ground black pepper. Toss to coat. Then spread the cabbage out in an even layer. Set aside.

Step 3

Peel the sweet potato, and then slice it into 1/4-inch coins or "medallions." Arrange the medallions in a single layer on a small (or large) baking sheet. Brush the tops with olive oil and sprinkle with kosher salt and freshly-ground black pepper. Set aside.

Step 4

Pat the chicken thighs dry with paper towels. For each thigh, gently loosen the skin, and then place 2 (or more) sage leaves between skin and meat. Dust the skin with kosher salt and freshly-ground black pepper.

Step 5

Warm the butter and olive oil in a skillet over medium heat. When the butter melts, add the chicken thighs skin-side-down. Sauté just until the skin turns chestnut brown -- 90 seconds to 2 minutes. Immediately remove from heat.

Step 6

Make 4 openings in the cabbage bed, and add a chicken thigh to each opening. Place this cabbage-and-chicken baking sheet on the center rack of the preheated oven; put the other baking sheet that holds the sweet potato medallions on the upper third rack.

Step 7

Bake until the cabbage turns brown and crisp around the edges, the chicken registers 165°F, and the sweet potato medallions are caramelized and tender -- usually 25 minutes.