Try this Marmellata di bergamotto recipe, or contribute your own.
Bergamots possess thick, volatile-oil-heavy rinds that require paper-thin slicing to soften evenly during cooking. A heavy chef knife works well if sharpened beforehand, though a mandoline speeds up the process significantly. Boiling the sliced fruit for five minutes removes the harshest bitter compounds while preserving the distinct aromatic oils. Drain the fruit completely through a metal colander before returning it to the pot with fresh water and sugar.
Citrus seeds contain high concentrations of natural pectin crucial for setting. Gather the discarded seeds and cores inside a clean piece of cheesecloth, tying the corners tightly with kitchen twine. Submerge this bundle directly into the simmering pot alongside the fruit and sugar mixture. Discard the pouch once the two-hour simmer concludes and the mixture thickens.
Place a small ceramic plate inside the freezer for ten minutes prior to testing. Spoon a half-teaspoon of hot marmalade onto the chilled surface and wait thirty seconds. Tilt the plate vertically; a properly set preserve wrinkles slightly and resists running. Ladle the finished jam immediately into sterilized glass jars while the temperature remains above 85 degrees Celsius.