Combine the pumpkin purée, apple juice, brown sugar, cinnamon, ginger, nutmeg, and cloves in a heavy-bottomed saucepan.
Stir the mixture thoroughly and bring to a boil over medium-high heat.
Reduce the heat to low and simmer for approximately 20 minutes, stirring frequently to prevent scorching and splatter.
Stir in the lemon juice and salt during the last minute of simmering.
Remove the saucepan from the heat and allow the mixture to cool to room temperature.
Transfer the pumpkin butter into sterilized airtight jars and store in the refrigerator for up to 3 weeks.