1. Heat the oven to 375°F. Put the beets and garlic on a large sheet of heavy-duty aluminum foil. Scatter on the orange zest and thyme, season with salt and pepper, and drizzle with the olive oil. Fold up the sides of the foil and crimp to make a tight packet. Slide the foil packet onto a baking sheet and into the oven. Bake for 1 hour.

2. Open the packet carefully (to avoid the steam) and check that the beets are tender by piercing one with the tip of a sharp knife. The knife should slide in easily; if it doesn’t, reseal the package and continue baking. Set aside to cool for 15 to 20 minutes. Using paper towels, rub the skins off the beets and cut the beets into chunks. Peel the garlic cloves. Discard the thyme and orange zest, saving any juices collected in the foil.

3. Drop about one-third of the beet chunks, the garlic, and any collected juices into a blender. Add some of the chicken broth and the honey. Before turning on the blender vent the lid by removing the pop-out center if there is one, or just open the lid a bit, and drape a clean dishtowel over the vented lid. Blend to a smooth purée and transfer to a bowl. Continue in batches, puréeing all the beets.

4. Stir in the orange juice and vinegar. Season to taste with salt and pepper. Cover and refrigerate to chill the soup thoroughly, at least 4 hours or overnight.

5. Meanwhile, stir the dill into the sour cream. If the sour cream is too stiff (it should be the consistency of lightly whipped cream), stir in a few teaspoons of cream or water to loosen it. Refrigerate until serving time. To serve, ladle the soup into cups or bowls and spoon a bit of the dilled sour cream onto each serving.