Preheat oven to 350 degrees.
Line your baking tray with parchment paper and set aside.
In a shallow plate, add one cup of powdered sugar and set aside.
In a large bowl, beat the egg whites with a pinch of salt using an electric mixer (or a hand whisk) until you achieve a shiny, white color and smooth, fluffy consistency.
Add the powdered sugar, lemon zest and almond extract in two stages and continue mixing until soft peaks form.
At this stage, use a spatula or wooden spoon and start adding the almond flour in small quantities and gently folding it into the egg whites. You should end up with a slightly hard but still sticky dough.
Portion the dough using a tablespoon (or small ice cream scoop). Use your hands to form small balls and then roll each ball in the plate of powdered sugar plate that we set aside in step 1. Tip: To prevent the cookies dough from sticking to your hands, generously dip your fingers and palms into the powdered sugar plate.
Place each ball on the lined baking tray and gently press the top with your finger.
Bake for 12 to 15 minutes until the tops start to crack and the bottoms turn golden.
Remove from oven and allow to cool on a rack.