4 pounds nectarines as purchased (about 8 very large nectarines, to yield 3 1/2 pounds prepared fruit)
1 1/2 cups lightly packed light brown sugar
1 cup granulated sugar
4 tbsp freshly squeezed lemon juice
1/2 teaspoon cinnamon
1/4 teaspoon ground dry ginger
Prepare a water bath canner and 6, half-pint jars for water bath canning. (You'll probably only need 5 jars, but better safe than sorry.)
Wash and stem nectarines, but don't peel. Remove the nectarine pit and rough chop the nectarine fruit. You should have 3 1/2 pounds of prepared nectarines after the fruit has been taken off the pit.
Add the nectarines, brown sugar and granulated sugar to a large, wide, non-reactive pot. Bring to a simmer over medium-high heat, stirring often so the nectarines don't scorch.
Cook the nectarines until they are soft and surrounded by a juicy sugar syrup, about 10 minutes. If you prefer a smoother textured jam, break up any large pieces of fruit with a potato masher, whisk, or fork at this point.
Add the lemon juice, cinnamon and ginger to your jam. Continue to cook, stirring often, until the jam reaches the gel point.
Turn heat under the jam to low, then quickly ladle the jam into clean, hot jars, leaving a 1/4 inch headspace. Remove air bubbles, adjust head-space and wipe jar rims carefully. Lid your jars according to manufacturer's directions, then transfer your jars to your canner.
Process jam ten minutes at a full boil. While jars are processing, set a kitchen towel on the counter in a draft free place.
After jars have processed, turn off the heat under your canner and allow the jars to sit in the canner for 5 minutes. Remove the jars and set on the kitchen towel. Jars should begin sealing almost immediately - you'll hear a sharp ping! as they seal. Leave jars alone for 8 to 12 hours to fully cool and set their seals, then check seals. Transfer any jar that hasn't sealed to the refrigerator and use it within 3 weeks. Store remaining jars at cool room temperature away from direct light. Jam is best used within a year.
Recipe by Northwest Edible Life at https://nwedible.com/nectarine-brown-sugar-jam/