Cook 4 each sliced carrots and celery stalks in salted boiling water, 5 minutes. Add 1 1/2 cups frozen pearl onions; cook 1 more minute, then drain. Cook 2 tablespoons each butter and sugar, and the juice from 1/2 lemon in a skillet until syrupy. Toss in the vegetables and season with salt and pepper.
Photograph by Antonis Achilleos