Preheat the oven to 375°F. Roast the beets: In a large bowl, toss the beats with the white balsamic vinegar and 2 tablespoons of the olive oil. Place the beets and the vinegar-oil mixture in a rimmed baking dish for pan and roast until tender when pierced with a toothpick or skewer, 45 minutes to 1 hour. Let the beets cool slightly; peel and dice them while they’re still warm.

Sprinkle the beet with the sugar, salt to taste, and the remaining tablespoon of balsamic. Let cool, then chop into 3/4-inch cubes.

Make the Roquefort vinaigrette: place half the Roquefort and the champagne vinegar in a bowl and sprinkle with salt and pepper. Slowly whisk in the remaining 3/4 cup olive oil until emulsified.

Assemble the salad: Place the beets, fennel, haricots verbs, and radicchio in a bowl, sprinkle with salt and pepper., Add half o fat vinaigrette and toss gently. Add more dressing if it’s too dry.

Scoop the salad onto four plates or a serving platter. Top with the avocado and remaining Roquefort. Sprinkle with chives and serve.