Plum Jam with Walnuts
Toast the walnuts in a dry pan. Remove the walnuts from the pan and cool.
Rinse the plums, cut into quarters, and remove the stones. Mix the plums with the sugar and lemon juice. Bring to a boil, stirring constantly. Cook the mixture for 5 minutes, continuing to stir until the jam begins to thicken. Add the walnuts to the jam and stir until combined. Fill the prepared jars to the brim with the jam, seal tightly, and cool completely.