Remove ends of lemons. Cut in half lengthwise, then cut a triangular notch down the middle to remove the center pith. Run your thumb along the inside of the notch to remove seeds, working over a bowl to catch any and all juice. Reserve seeds (they’re full of valuable pectin and we’ll need them later). Thinly slice remaining lemon into strips using a sharp knife or mandoline. You should have about 4 cups of lemon slices.

Transfer to a large bowl along with Montmorency tart cherry juice and 1 cup water (filtered, if necessary). Secure any seeds in a tea ball or length of cheesecloth tied into a bundle and submerge into the liquid; cover tightly with plastic wrap and refrigerate overnight or up to 2 days.

When you are ready to can, prepare canner and wash/sterilize your half-pint mason (or equivalent) jars. Keep jars in hot (not boiling) water until ready to use. Warm lids in hot (not boiling) water to sterilize and soften seal.

Remove the cheesecloth bundle; squeeze out any remaining juices and discard the seeds. Pour the soaked fruit and all liquid into a large, non-reactive saucepan.

Bring to a simmer over medium-high heat and cook, stirring occasionally, for 20 minutes.

Meanwhile, place sugar in a bowl. Whisk in pectin until evenly incorporated. Prepare calcium water according to package instructions.

Once marmalade has been simmering for a solid 20 minutes, remove from heat and measure. You should have approximately 4 cups of cooked fruit (measuring is important to ensure the proportion of pectin and sugar is correct).

Return to medium-high heat and stir in calcium water and lemon juice. Bring to a vigorous boil, then add sugar mixture, stirring until sugar is dissolved and mixture returns to a full rolling boil that can’t be stirred down, about 2 to 3 minutes. Remove from heat.

Ladle hot sauce into jars, leaving 1/4-inch of headspace. Wipe jar rims and threads. Screw on lids and rings. Process in a boiling water bath for 10 minutes. Remove from water and let cool completely, 12 to 24 hours. Check seals. Any unsealed jars should be refrigerated and used within 3 weeks.

Recipe courtesy of Lindsay Landis, LoveandOliveOil.com