1. Put the hazelnuts in the bowl of a food processor and pulse them until very fine; they should be the consistency of coarse polenta. (See photo, in post.)
2. Transfer the ground nuts to a bowl and add the rice flour (if using all-purpose flour, sift it in). Cut the butter into pieces then add the butter, sugar, and salt to the dry ingredients. Use your hands to mix all the ingredients together until the butter is dispersed and completely incorporated. The dough should be very smooth and hold together. If not, knead it until it does.
3. Divide the dough into three equal pieces and roll each piece until it’s 3/4-inch (2cm) round. Try to get them as smooth as possible, with no cracks. If the dough is too long to work with as you roll them out, you can cut the dough at the midway point and work with it in batches.
Chill the dough logs until firm on a small baking sheet or dinner plate lined with plastic wrap or parchment paper.
(Terresa recommends refrigerating them for 2-3 hours, but we put them in the freezer and they were cold within 15 minutes.)
4. Preheat oven to 325ºF (160ºC) and line two baking sheets with parchment paper or silicone baking mats.
5. Working with one length of dough at a time, keeping the others in the refrigerator or freezer, cut off equal-sized pieces using a knife or pastry cutter. The ideal is 5 grams each, if working with a scale. The fastest way to do it is to cut one to the right weight, then hold that one alongside the logs and use it as a template to cut the others. Once you’ve cut a length of dough, roll the pieces into nice little balls and place them on the baking sheet, slightly spaced apart (as shown.)
If you don’t have a scale, simply roll the dough to the size of a marble, trying to keep them as similar in size as possible.
6. Continue cutting the dough and rolling it into little balls. Bake the cookies for 10 to 14 minutes, rotating the baking sheets in the oven midway during cooking, until the tops are lightly golden brown. Let the cookies cool completely.
7. In a clean, dry bowl set over a pan of barely simmering water, melt the chocolate until smooth. Put a chocolate chip-sized dollop of chocolate on the bottom of one cookie and take another cookie, and sandwich the two halves together.
(Terresa uses a spoon but I make a little parchment paper cone and pipe the chocolate. I also find it goes faster if you line the cookies up, side-by-side, bottom side up, and pipe spoon chocolate on one side of a number of them at a time, then sandwich them together, then doing another batch, until they’re all filled.)
Once filled, set the Baci di Dama sideways on a wire cooling rack until the chocolate is firm.