Rinse beets thoroughly. Arrange snugly in a shallow baking dish and pour a little water into it so it pools in the pan. Cover tightly with foil, thenĀ roast until the beets are cooked through, about 40 minutes for medium-sized beets. Let sit until cool enough to touch, then rub off the skins and cut into quarter-inch slices. Place in a quart-sized jar.
While the beets are roasting, place vinegar in a medium-sized pot along with bay leaf salt, juniper berries, and peppercorns. Bring to a boil, stirring until the salt dissolves. Pour over the beets. Let cool, the refrigerate overnight before serving.