This is probably the recipe doxdogy is talking about, but here goes:
1 cup mayo
1 cup sour cream
1 envelope dried vegetable soup (any brand)
1 small can of water chestnuts, finely chopped
1 pkg of frozen, chopped spinach, thawed with the excess liquid squeezed out
Mix everything together the night before and refrigerate overnight (it tastes fine if you make it the same day, but I like the overnight thing to allow the flavors to meld)
Serve in a hollowed out bread bowl (I usually use a sourdough bread bowl, plus an additional loaf of sourdough for serving.
Have fun and congrats grandma!