Add the sugar and lemon zest to a bowl and mix well with your fingers.
1/2 cup granulated sugar, zest of 1 lemon
In a stand mixer fitted with the paddle attachment (or in a large bowl), mix the butter on low speed until smooth and creamy, about 1 minute. Add the sugar to the mixer and beat until smooth and velvety (about 1 minute).
1 cup butter
Add the salt and the egg yolks, one at a time, mixing on low speed after each one. Still on low speed, add the flour, mixing until just combined (don't overmix, the dough should be clumpy and soft).
Remove bowl from stand mixer and stir in rosemary and pine nuts until evenly distributed.
2 tablespoons finely chopped rosemary, 1/3 cup toasted pine nuts
Turn the dough out onto a piece of plastic wrap on the counter and knead it gently a few times. Divide it in half and shape each half into a 9-inch log, about 1 1/2 inches wide. Wrap the logs in plastic wrap and refrigerate for 2-3 hours (can also freeze at this point for about 2 months).
Preheat oven to 350 degrees. Line two baking sheets with parchment paper or silicone baking liners. Using a sharp knife, slice the log into 1/2-inch-thick rounds. Put them on the baking sheets, leaving about 2 inches between each round.
Bake cookies until golden and brown around the edges, about 18-22 minutes, changing the position of the baking sheets halfway through. Let cool on the sheets for a couple of minutes and then carefully transfer to a wire rack to finish cooling.
Notes
** Note: If you want to get really fancy, roll the sabel log in a little sugar and crushed nuts and/or rosemary before baking to make the edges stand out.If you like my articles about cooking and gardening, subscribe to my weekly newsletter, where I share free recipes and gardening tutorials.