These are family favorites that we've been enjoying since the early 1960s. The solid chocolate mint discs/wafers have been hard to find over the years. Now the most-recommended substitute is the small Andes mint. Rather than placing the dough on the cookie sheet and pressing the mint into it, I enclose the mint in the dough with my hands. First I break each Andes mint into two pieces. It's a lot easier to enclose the two stacked on top of each other, than trying to get the dough to cover one long rectangular piece. Then I take a healthy tablespoonful of chilled dough (should be chilled at least 2 hours after first) and roll it into a ball in the palm of my hand. Then I flatten it slightly, gently press in two mint pieces, and then use the heel of my other hand to bring up the edges of the dough over to cover the mint. The side facing upward becomes the bottom of the cookie. You should end up with a slightly rounded ball of dough with the mint hidden inside. After they're all placed on the cookie sheet, put a half walnut on each. 9-12 minutes is the best timing for mine. I buy two packages of Andes mints, 28 pieces each. No way have I ever made 100 with this recipe - maybe 55-60 is more like it.