- In small bowl, combine yogurt, mint and chives.
- Cover and refrigerate.
- Preheat oven to 400 °F.
- Cut beet greens off beets and set aside.
- Thoroughly scrub beets; cut off both ends.
- In large bowl, combine oil, garlic, rosemary, cayenne, salt and pepper.
- Place beets in bowl and mix to lightly coat.
- Place beets on baking sheet (reserve marinade) and bake, tossing occasionally, until tender, 45 to 55 minutes.
- While beets are roasting, wash and remove stems from greens and chop.
- In heavy-bottomed sauté pan, heat reserved marinade.
- Add onion and saute until soft, about 6 minutes.
- Add greens and cook until greens are thoroughly wilted, about 3 minutes.
- Remove from heat and season with salt and pepper.
- Place bread slices on baking sheet and toast on both sides, about 3 minutes.
- When beets have cooled (you may peel them if desired), cut in half and thinly slice.
- Place in medium bowl and add brown sugar and vinegar.
- Toss and season.
- To serve, place a generous amount of beet greens on top of toasted bread.
- Top with beets and garnish with yogurt-herb dressing and a sprinkle of chives.