1
Rinse the apples in warm water and transfer to a chopping board. Cut the apples into quarters - core, rind and all - and then slice each quarter crosswise so you have 8 pieces. Transfer all the pieces to a large Dutch oven or pan. Rinse the blackberries thoroughly, then add them to the pan with the apples. Pour in 8 cups of water. (For my 10.5-inch-wide, 5.5-inch-deep pan, this amount of water should just cover the fruit and give it room to float freely; if your pan is slightly larger, add more water until the fruit floats. (If your pot is smaller, put the water in 8 cups.)
2
Bring the pan to a boil over high heat. Reduce the heat to medium, keeping the heat active, and cover the pot with a lid. Cook the fruit until the apples and berries are more or less falling apart, about 2 hours. If needed, add more water throughout the cooking process to keep the fruit floating freely.
3
While the fruit is cooking, hang a colander or coarse strainer large enough to hold all the fruit over a large bowl so that the bottom of the colander does not sit in the bowl, but hangs over it.
4
Remove the pan from the heat and pour the cooking liquid and fruit into the colander; clean and reserve the pan. Cover the fruit and strainer with cling film and transfer to the fridge. Leave overnight or at least 8 hours to sit undisturbed - this will allow every drop of liquid and pectin to escape from the fruit. Place 5 small plates or saucers in the fridge overnight.
5
The next day, place a fine sieve, preferably lined with a coarse cotton cloth, over the reserved pan. Pour the drained liquid slowly into the sieve, without squeezing the solids in the sieve, allowing the liquid to drain completely into the pan; this helps to keep the juice as clear as possible, so does the jelly. Discard any sediment from the cooked fruit, the sieve and the coarse cotton cloth in the strainer. You should have about 6 cups of juice.
6
Add the sugar and lemon juice and a large pinch of salt. Place the pan on a high temperature and bring to the boil. Let the jelly cook for about 10 minutes. Remove the pan from the heat and allow the bubbles to settle, then ladle some of the liquid onto one of the chilled plates. Place the dish back in the freezer for 2 minutes. Remove the plate and press your fingers against the surface of the plate and through the liquid. If the liquid wrinkles, the jelly is ready. If it is still too loose, put the jelly pan back on the heat and once it starts to boil again, cook for 2 minutes more. Remove the pan from the heat and check the setting again. Repeat until the jelly is ready. This process usually takes 12 to 15 minutes, but it is best to start checking after 10 minutes.
7
Once the jelly has set, add the amaro. Bring the jelly back to the boil and then immediately remove the pan from the heat. If storing the jelly in jars, use a long-handled spoon or large heatproof jar or liquid measuring cup to immediately transfer the hot jelly to clean glass jars, filling them to within 1/8 inch of the rim. Cover and cool to room temperature, then store the jelly in the refrigerator. If storing in a plastic storage container, cover and allow the jelly to cool in the pan for 15 to 20 minutes before transferring to the container. Store the jelly in the fridge for up to 3 months.
