Preheat oven to 350°. Line a baking sheet with parchment paper.
In a large bowl, beat together butter and sugar with a mixer at medium-high speed until smooth and creamy. Beat in vanilla extract and salt. With mixer at low speed, gradually beat in flour until dough comes together. (It will be dry, but don’t panic.) Beat in nuts until combined.
Portion dough and roll into 1½-inch balls. Place dough balls 1 inch apart on prepared baking sheet. Press a thumb into centers of dough balls to create an indentation.
Bake until cookies are lightly browned around edges, 13 to 15 minutes. Let cool completely on a wire rack.
Spoon approximately ¼ teaspoon Almond Icing into centers of cookies. Let icing set slightly before serving.
Recipe by TeaTime Magazine at https://teatimemagazine.com/valerie-burns-serves-up-a-new-mystery-series-with-two-parts-sugar-one-part-murder/