Roast the BeetsPreheat oven to 400 degrees F.
In a large bowl toss the beets, shallots, rosemary, and olive oil. Place into a foil pouch and roast in the oven for 40 minutes.
Pickle BeetsRemove the skin from the Roasted Beets and slice thinly. Arrange in 1-quart jars alternating layers with the onion. In a small pot boil the rest of the ingredients and pour over the beets. Tightly lid the jars and place in the refrigerator for 3 to 7 days before serving.