In a small baking dish add the beets, onion, carrots, sage sprigs, tablespoon olive oil and season with salt, pepper and pinch of pepper flakes. Toss gently to coat and roast for 40-45 minutes. Remove from the oven and set aside. (leave the oven on)

Add the yams to the oven and bake for 45-60 minutes, or until soft when pierced with a knife. Remove and allow to cool just until you are able to handle them. Put the yam flesh in a medium bowl and add 2 teaspoons butter, sour cream, orange zest and season with salt and pepper. Set aside.

While the vegetables are cooking, heat an oven proof skillet over high heat. Add 1 teaspoon butter and add the mushrooms, sage and season with salt and pepper. Brown the mushrooms, about 4 minutes. Remove from the skillet and add to the roasted vegetables.

In a medium bowl, add the flour, salt and pepper and toss the lamb pieces in the flour mixture, removing any excess flour. Return the skillet to medium-high heat and add the remaining butter. Add the lamb in a single uncrowded layer and brown on each side. Remove to the roasted vegetable dish as they brown, repeat with remaining lamb.

Add the wine and deglaze the pan scraping up the browned bits in the pan, about 1 minute. Add the slivered garlic and sage and add the roasted vegetables, mushrooms and lamb. Toss to coat in the red wine mixture and remove from the heat. Top with the yam mixture and bake at 425 degrees F for 25 minutes, or until the top is starting to brown and the lamb mixture is bubbling around the edges. Remove and serve immediately.