Begin by peeling the oranges, ensuring you remove as much of the white pith as possible to prevent bitterness.
Puree the peeled oranges using an immersion blender or regular blender until smooth.
In a medium saucepan, combine the orange puree, sugar, and optional spices.
Simmer the mixture over moderate heat, stirring occasionally, for 20-30 minutes until the jam thickens. To test the consistency, drop a small amount of jam onto a plate that has been chilled in the freezer. If it holds its shape, the jam is ready.
Pour the hot orange jam into prepared, sterilized canning jars. You can either store the jars in the refrigerator or process them in a water bath canner for 10 minutes if you plan to store them long-term.