Citrus Orange Marmalade

Begin by carefully removing the outermost layers of three oranges and one lemon, discarding them. Peel off the skin and pith from these four citrus fruits, setting them aside. Cut each of the remaining oranges in half lengthwise and slice into thin pieces, discarding any seeds that come up during the process. Place all of these citrus slices in a large bowl and cover them with water, covering the bowl to keep it refrigerated for at least 8 hours or up to 24 hours.

Next, combine the citrus slices and water in a large saucepan or Dutch oven. Bring this mixture to a boil over high heat, stirring occasionally as it reaches its boiling point. Once boiling, reduce the heat to medium and simmer, uncovered, stirring every now and then, until the orange rinds have softened and can be easily cut with a spoon, taking about 45 minutes to achieve this. You may notice foam rising to the top during this time, so be sure to skim it off.

Before proceeding, inspect four ½-pint canning jars for any signs of damage, such as cracks or rust on the rings. Discard any jars that are not in good condition. Immerse these clean jars in simmering water until your marmalade is ready.

Wash any new, unused lids and rings in warm soapy water before using them. Place a small plate in the freezer to test the consistency of your marmalade later.

Add sugar to the orange mixture and bring it to a boil over high heat, stirring occasionally as it reaches its boiling point. Continue cooking the mixture until the liquid has slightly reduced and the bubbles are slightly larger in the center, taking about 40 to 45 minutes. During this time, a thermometer should read 220 degrees F (104 degrees C). The mixture will remain between 212 degrees F (100 degrees C) and 216 degrees F (102 degrees C) for most of this time, rising to 220 degrees F (104 degrees C) when enough liquid has evaporated.

To check the consistency of your marmalade, remove the plate from the freezer and spoon a small amount onto it. Return the plate to the freezer for 1 minute, then remove and test the marmalade by pulling a finger through it. If it leaves a clean trail, your marmalade is ready. However, if it's still runny and doesn't leave a clean trail, return the mixture to the pot and boil it over medium-high heat for 3 minutes. Remove from heat, retest the thickness using the plate again, and repeat if necessary until you reach your desired consistency.

Carefully pour the marmalade evenly into the prepared canning jars, letting them cool to room temperature, uncovered, for about 3 hours. Once cooled, seal the jars and chill them until the marmalade has set, at least 2 hours. Finally, store the jars in the refrigerator for up to 2 weeks.