0.25 cup **(around 70 grams)** unsalted, softened butter
0.25 cup **(around 70 grams)** rendered fat
0.5 cup sugar
0.5 teaspoon kosher salt
1 large egg
2 cups all-purpose flour
steps
Lightly grease the bottom and sides of a baking dish and line it foil or parchment paper
Beat the butter, rendered fat, sugar, and salt until pale and fluffy **(around 2 minutes)**
Add the egg and continue beating until combined
Add the flour and beat until dough *just* comes together
Scrape dough into prepared pan and spread into an even **(0.5 inch thick)** layer
Use a sharp, thin knife to lightly score the surface into 3x1-inch rectangles **(do not cut all the way through)**
Use a skewer to poke 2 holes into each rectangle
Refrigerate until dough is chilled solid **(around 1 hour)**
Preheat oven to 325 degrees fahrenheit
Once preheated, transfer the pan to the oven and bake, rotating once halfway through, until the dough is set and just barely browned at the edges **(16-18 minutes)**
While the shortbread is still hot, use a thin knife to neatly slice into rectangles and sprinkle with flaky **(Maldon)** salt.
Let cool completely in the pan before removing and serving.
notes
This recipe works especially well with duck fat, but seems amenable to any fats. I've so far liked it best with duck fat, but found it tasty with lard as well.
Spreading the dough before baking can be difficult, so once you've done as good as you can with your hands, use a flat bottom glass or other instrument to try and make the dough height as even as possible. This will ensure you don't get dry/ overdone spots in the resulting cookies.
The cookies go great with coffee or tea.
Duck fat doesn’t behave exactly like butter. It’s nearly liquid at room temperature and, like lard or shortening, contains no extra water, which minimizes gluten development when it’s added to pastry doughs. Using equal amounts butter and other fat seems to minimize any potential negative effects while allowing the alternate fats flavors to come through.
The original Saveur recipe calls for 140 grams of each fat, which seems like far too much and doesn't align with the "0.25 cup" amount they give.