If making jam to preserve fruit and not for immediate use, prepare water-bath canner, jars and lids according to manufacturer’s instructions (follow along with instructions on pectin).

Blanche, peel, and pit plums, core apple and pears, and finely chop. If using a food mill, do not peel and simply cut fruit into smaller quarters.

Combine prepared fruit and lemon juice (if required) in an 8-quart saucepan. Cook for about 5-6 minutes on medium heat until fruit begins to produce juice and soften. Add butter, if using.

Bring mixture to a full rolling boil that cannot be stirred down (meaning you can still see bubbles even when you stir it), over high heat, stirring constantly.

If using food mill, gently spoon softened fruit mixture into mill over a bowl until all that remains in the mill is the peels of the fruit used. Will take some elbow grease and maybe about 10-15 mins extra if doing this step.

Return fruit mixture to stove top and bring back up to temperature. Add entire measure of sugar, stirring to dissolve. Return mixture to full rolling boil and stir constantly for 1 minute.

Remove from heat and add in vanilla extract/vanilla bean paste and taste jam for consistency and flavor. Add more lemon juice or sugar if necessary.

Boil water and pour into mason jars to prevent hot jam from breaking them. Pour out water and pour jam into jars carefully with a funnel, covering with lids. Keep in the fridge for up to 3 weeks. To keep in the pantry (a cool, dark place) for up to 1 year, boil filled jam jars in a saucepan with water, covering 1-2 inches above the lids for 10 mins to seal. Jars are sealed successfully when you can press the tops of the lids and they don't pop or bounce back at you. Enjoy on toast, waffles, muffins, with ice cream, or on sandwiches!