Rick Field joins Martha to make his award-winning phat beets.
Bring a large pot of water to a boil. Add beets and cook until easily pierced with a fork, about 30 minutes. Drain beets and place under cool running water. When beets have cooled, remove skins and cut beets in half lengthwise. Cut each half crosswise into 1/4-inch thick slices.
Place 6 clean 1-pint jars right side up on a rack in a boiling-water canner. Fill the canner and jars with hot water, about 1-inch above the tops of jars. Boil jars over high heat for 10 minutes. Remove and drain hot sterilized jars one at a time, reserving hot water for processing filled jars. Place jars on a wire rack set over a rimmed baking sheet.
In another large pot filled with water, bring to a boil over high heat and reduce to a simmer; add cleaned lids and lid rings. Simmer lids for 10 minutes; do not boil, as this may cause problems in sealing jars. Drain lids and set aside.
Fill each jar with 2 pieces of ginger and 1 sprig rosemary. In a large bowl, mix together onions and beets. Pack each jar with onion and beet mixture up to within 1/2 inch below the rim of the jar.
Place allspice, cinnamon stick, and cloves in a piece of cheesecloth; tie cheesecloth with kitchen twine to enclose. Place in a large saucepan along with cider vinegar, 2 cups water, lemon juice, and brown sugar. Bring to a boil over medium-high heat, and reduce to a simmer. Cover and let mixture simmer about 10 minutes.
Immediately pour hot vinegar mixture over the beet mixture in each jar. Put lids and rings on jars and tighten; do not over-tighten. Reheat water in the canner until it reaches at least 180 degrees, within 10 minutes of filling the jars. Place filled jars into the canner one at a time, using a jar lifter that is securely positioned below the neck of the jar. Keep jars upright at all times.
Add more boiling water, if needed, so that water covers jars by at least 1 inch. Increase heat to high and cover. Once water begins boiling, heat jars for 7 minutes. Turn off heat and gently transfer jars to a wire rack set over a rimmed baking sheet, taking care not to tilt jars and spacing each jar at least 1 inch apart. Avoid placing jars on a cold surface or near a cold draft.
Let jars sit undisturbed until fully cooled, 12 to 24 hours. Do not tighten ring bands on the lids or push down on the center of the flat metal lid until jar has cooled completely.
Once jars have cooled completely, test to make sure each jar is completely sealed. Press down on the middle of the lid with a finger. If lid springs up when finger is released, the jar is unsealed. Store sealed jars in a cool place for at least 2 and up to 4 weeks to allow flavors to thoroughly combine. If any of the jars are unsealed, store in the refrigerator and used within several days.