Follow our Magical Marinated Maraschino Cherry recipe. As noted there, you will only need half the syrup. Put the remaining syrup into a new mason jar. You can also repurpose the glass Luxardo jar. It works great for this.
Add raisins to the jar.
Be careful not to fill the jar above the liquid line. You want all of the raisins resting below that. If you're got the space, add more raisins.
Seal the jar, label and date it.
Put the jar into a dark cupboard.
Let the raisins rest for about 6 months. This will give them ample time to suck up the flavor from the syrup.