Step 1

Remove the stems and pit the cherries. Put them in a large non-reactive pot. If using sweet cherries, add 2-3 tablespoons of water to the pot. (Sour cherries will exude enough liquid on their own so no need to add additional water.) Put a small plate or saucer in the freezer.

Step 2

Cover the pot and cook over medium heat, stirring occasionally, until the cherries are wilted and cooked through, about 10 minutes.

Step 3

Remove the lid and stir in the sugar and lemon juice. Increase the heat to medium-high and cook, stirring frequently until the mixture thickens. It's hard to say how long it will take, but when the mixture resembles the sixth picture in the post, the one in the pot with the bubbles, turn off the heat and test the jam by putting a small spoonful on the frozen dish. Return the dish to the freezer for a few minutes until the jam on it is cool. Run a spoon through it and if the liquid is very thick and leaves a clear patch, as shown in the photo in the post, it's done. If not, return the plate to the freezer and continue to cook the jam, testing it at various intervals, until it's done. (If you want to use a thermometer to check the jam, it should be ready somewhere between 220º and 225ºF, 104º-107ºC.)

Step 4

When ready, turn off the heat and stir in the almond extract or liqueur (or both, if you wish). If desired, you could add an extra squeeze of lemon juice to balance the sweetness. Ladle into clean jars.