Line rimmed baking sheet with wax paper. Set aside.
In a food processor, blitz the almonds and granulated sugar into a fine powder.
In the bowl of a stand mixer fitted with paddle attachment, beat butter on medium-high until light and fluffy.
Add almond-sugar mixture, flour, cornstarch, confectioners’ sugar, egg, and salt. Mix until thoroughly combined.
Divide dough into 50 walnut-sized balls, rolling each into a sphere. (Each ball should be roughly 10 grams.) Place dough balls on rimmed baking sheet, then chill in freezer for at least 1 hour.
Heat oven to 340°F. Line two baking sheets with parchment paper.
Retrieve dough from freezer. If you weren’t able to get perfect spheres during step 5, you may wish to quickly reroll your dough balls at this point and pop them back into the freezer for 15 or so minutes. (We had to do this since we were baking the cookies on a very hot, humid Atlanta summer afternoon.)
Place chilled dough balls on parchment-lined baking sheets. (Hold onto the rimmed baking sheet, as you’ll need it later.)
Bake for about 20 minutes, rotating pan halfway through. Cookies are done when edges are set and golden.
Allow cookies to cool on baking sheets for 5 minutes, then transfer to a wire rack to cool completely.
Once cookies are totally cool, spread ¼ to ½ teaspoon of Il Colle del Gusto Noccioliva on half of the cookies. Top with remaining cookies. Place all “kisses” on rimmed baking sheet. NOTE: No need to squeeze the cookie halves together; just let gravity do its thing.
Refrigerate for 15–30 minutes or until filling is set.