About 240 ml (1 cup) brewed strong coffee, espresso or water
A few tablespoons powdered sugar, for dusting
Preheat the oven to 180°C (350°F), with rack placed in the middle of the oven. Line 2 baking sheets with parchment paper (or silicone baking mats) and set aside. Line a smaller baking sheet with parchment paper, add almonds and toast them for about 10 minutes, until fragrant. Remove from oven (keep the oven on) and cool for a few minutes. Coarsely chop the almonds and set aside.
In a big bowl, stir together the flour, sugar, cocoa, baking powder and cinnamon. Lastly add almonds and lemon zest. Make a well in the center and add 1/2 coffee. Start stirring the dough and the rest of coffee. Mix until dough starts to form. Continue kneading the dough with your hands in the bowl until a stiff dough forms (you want the texture of modeling clay). Divide the dough into quarters.
Slightly flour your working surface and roll a piece of dough into a 50 x 2,5 cm (20 x 1 inch) rope. Press down to slightly flatten the rope. Using a sharp knife (or bench scraper) cut it on the diagonal into 3 cm (1 1/4 inch) diamond shapes.
Arrange the cookies on the prepared baking sheets, leaving at least a 1,5 cm (1/2 inch) space between them. Repeat with the remaining dough. Bake until the cookies feel set, but still somewhat soft, about 15 minutes. The tops will crack, but the cookies will not darken any further.
Transfer the baking sheets to a wire rack to cool. Once the cookies are cool enough to handle, transfer them directly to the racks ad let cool completely. Generously sift powdered sugar over the cookies. Store cookies in airtight containers for up to two weeks.
As mentioned above, you can use water instead of coffee in this recipe. However, coffee gives the cookies that nice brown color and it also intensifies the flavor of cocoa.