Zest the orange first and set the zest aside. Then squeeze out the juice and slice off 2–thin strips(3-4"x½") of the peel (white pith included). You’ll simmer these strips with the jam to release natural pectin and a hint of citrus depth and then remove at the end. See notes.
1½ Tablespoons orange zest, 2 Tablespoons orange juice, 2 strips of peel with white pith 3-4" x ½"
Grate the Granny Smith apple. Include as much of the peel as possible for the natural pectin.
½ cup Granny Smith Apple
In a small heavy saucepan, combine pumpkin purée, grated apple ,apple juice, sugar, orange zest, orange peel strips, and juice, ginger, lemon juice, and salt. Stir well to mix.
1½ Tablespoons orange zest, 2 Tablespoons orange juice, ½ cup Granny Smith Apple, 15 ounce pumpkin purée, 2/3 cup apple juice, 1½ cup granulated sugar, 2 teaspoons ginger paste, 4 teaspoons lemon juice, 1 pinch of salt, 2 strips of peel with white pith 3-4" x ½"
Clip the candy thermometer on the side of the pot ensuring the tip will be immersed the jam but is not touching the bottom of the pot.
Bring the mixture to a gentle boil over medium heat, stirring every few minutes, scraping the sides and bottom so that the starchy pumpkin does not stick, then reduce to a simmer. Keep heat at a gentle simmer until about 200°F stirring every 10 minutes. Then increase to medium and stir every five minutes. Time it for about 20 minutes. (See notes.) Do the cold plate test (see blog post).
Remove and discard the orange peel strips. Taste and adjust sweetness or acidity. Add a splash more lemon juice (up to one teaspoon) if you want extra brightness. Stir in the vanilla extract and pinch of salt.
1 teaspoon pure vanilla extract, 1 pinch of salt
Let cool completely, then transfer to a clean jar. Store in the refrigerator for up to 2 weeks. This jam is small batch and will make about two cups total. Make one jar for you and give the other away!