Preheat your oven to 350 degrees and line 2 cookie sheets with parchment paper.
Place the almonds on the cookie sheet and bake for 10 minutes or until fragrant and toasted brown. Let them cool and then coarsely chop them or leave them whole.
In a large bowl, beat the sugar and eggs on high speed until thick pale and fluffy (about 7 minutes). Mix in the vanilla, almond extract, and lemon zest. Make sure you scrape down the sides of your bowl to fully incorporate the ingredients.
Add the flour, baking powder and salt. Mix until just combined. Fold in the almonds and chocolate.
Wetting your hands, transfer the dough onto prepared cookie sheet. Mold the dough into 2 log shapes that are about 6 inches long and 4 inches wide. This does not have to be perfect. If the dough still sticks to your hands, wet them again. Alternatively, you can make one long log that is 12 inches long and 4 inches wide. Sprinkle the coarse sugar on top.
Bake the logs for about 25 - 30 minutes or until firm to the touch. Let the tray rest on a wire rack to cool for 15 minutes. Afterward, using a serrated knife, cut the logs diagonally into 2 cm wide slices. Place the cut side down and place it back in the oven to cook for another 10 minutes or until dry enough to the touch.
Remove and let cool before storing in an air tight container.