Preheat the oven to 425°F
1. In a small jar, combine the vinegar, garlic, and olive oil. Season with salt and pepper to taste, put the lid on the jar and shake it up to combine.
2. Cut the beet tops and tails off and discard. Scrub the soil off the beets and dry with a paper towel. Place the beets in an oven-proof dish and coat with olive oil. Roast for approximately 45 minutes or until tender. Remove and set aside to cool.
3. Add the salad greens and radicchio to a large bowl, drizzle roughly 6 tablespoons of the vinaigrette on the greens and toss to combine. Top the dressed greens with the onion, crumbled blue cheese, and toasted pecans. Slice the beets and arrange on the top and serve immediately.