1. Bring 1 3/4 cups apricot nectar and spices to a boil in a small saucepan over high heat, covered. Reduce heat and simmer 10 minutes. Strain, then measure 1 1/4 cups, adding more juice if needed.
2. Combine pectin and 1/4 cup sugar in a 5- to 6-qt. pot. Stir in plums, then spiced juice, lemon juice, and butter. Bring to a brisk boil over high heat, stirring often.
3. Add remaining 1 1/4 cups sugar. Return jam to a brisk boil, stirring. Cook, stirring constantly, 1 minute. Remove from heat.
4. Ladle jam into heatproof jars, distributing fruit evenly, and close with lids. Let cool to room temperature, inverting jars occasionally to distribute fruit. Keeps, chilled, up to 1 month.
*We used Santa Cruz Organic Apricot Nectar.
Note: Nutritional analysis is per tbsp.