Using a small serrated knife (with teeth), make a slit into each date, creating an opening. Using a butter knife or spreader, fill the dates with about a teaspoon of cream cheese, smoothing the tops. Press a walnut half (curly side facing up) into the cream cheese on each date.
Serve immediately or store the dates in the refrigerator, covered in a plastic container until later. Note that the cream cheese will start to dry out after awhile, so fill the dates as close to serving time as possible for best results. Store any leftovers in the refrigerator.
For anyone with a nut allergy, you might want to try using sunflower seeds in place of the walnuts.As for other nuts, I've tried pecans and cashews with the dates, but walnuts work best. Also, I prefer the texture of block cream cheese for this recipe, as opposed to whipped cream cheese.