Bring 2 cups of water to boil in a large saucepan. Trim the tops of mandarins and cut away the peels, removing the white pith from the citrus flesh.

Next, prepare the citrus peels. Slice the peels into thin slices, then dice into smaller pieces, depending on how big you like the chunks of the citrus zest in your marmalade. I like the very small pieces, so I diced these into ¼ inch pieces. Once you've got 2 cups of citrus peel, discard the rest and set these diced pieces aside in a medium bowl.

Once the water has been brought to a full rolling boil, pour the water over the diced peels. Add ½ teaspoon kosher salt. Give the peels a quick stir and set aside to cool slightly. This step helps to soften the bitterness of the mandarin peels. Next, prep the mandarin segments for the next step.

Using a sharp knife, and working over a large bowl, slice the segments to separate the citrus flesh from membranes. Take care to work over a bowl to catch all the juice as you separate the mandarin segments from membranes. Allow segments to fall into the large bowl as you work. Once all the fruit is removed from membranes, give the membranes a good squeeze to wring out any remaining juice from the mandarin. We’ll use the juice and fruit segments to make our marmalade.

Add the juice and mandarin segments to a large pot. A dutch oven or non-reactive pot works well. Pour the maple sugar over the fruit and stir to combine. Bring to a full boil and cook, stirring regularly, until the mixture starts to bubble and thicken, about 15 minutes.

Strain the mandarin peels and add them to the pot. Add a sprig of rosemary and lemon juice. Stir everything to combine. Insert candy thermometer to track temperature for the gel test. Ideally, you want the marmalade to reach a temperature of 220 degrees Fahrenheit for the optimal gel set.

When the marmalade has finished cooking, remove from heat. Funnel the hot marmalade into the prepared half-pint jars. Wipe the rims. Apply the lids and rings to the half pint jars. Here, you have the option to either freeze or process in a boiling water bath.

Once ready to store, make sure to label and date your Mandarin Marmalade. This easy recipe freezes well for up to 6 months.