Instructions:
- In a medium heavy-bottomed saucepan or Dutch oven, whisk together the pumpkin purée, apple juice/cider, both sugars, lemon juice, and all the spices (cinnamon, ginger, nutmeg, allspice, and salt). Ensure the sugar is fully incorporated.
- Place the mixture over medium heat. Bring it gently to a low simmer, stirring frequently to prevent the bottom from scorching.
- Once simmering gently, reduce the heat to low, maintaining a very gentle bubble. Allow the mixture to cook uncovered for 40 to 50 minutes, letting it reduce and thicken.
- Stir every 5 to 7 minutes, scraping the bottom and sides of the pan thoroughly to prevent burning, as the pumpkin will thicken quickly.
- The pumpkin butter is ready when it has visibly reduced by about one-third, darkened slightly in colour, and coats the back of a spoon thickly.
- Remove from heat. Allow the butter to cool slightly before transferring it immediately to clean, airtight storage jars. The butter will thicken substantially further as it cools completely.