1. In a large pot, cover the beets with salted water and bring to a boil. Reduce heat to simmer and cook until berries are tender, about 30 minutes. 
2. Drain the beets and run under cold water until cool enough to handle. Gently rub the skins off.
3. Lightly toast the walnuts in a dry skillet over medium heat. Set aside to cool.
4. Slice the beets into 3-mm (⅛-in.) rounds and arrange on a platter. Drizzle with the vinegar and olive oil, and season with salt and pepper. Sprinkle with the walnuts, cheese, and thyme; serve.

Chef’s secret

This salad is equally good warm or cold. To save time, create the platter the night before, refrigerate and dress right before serving.