Prepare the flax egg by mixing the flaxseed meal with water, set aside for 10 minutes.

Mix the soft butter with the sugar and zest of one orange with a wooden spoon.

In a another bowl, combine flour, cacao powder and baking powder.

Add the flax egg to the butter and gradually add the flour mix and 1 - 2 tablespoons of fresh orange juice. The cookie dough should be soft and and easy form into a ball without sticking to your hands. Either add more flour or orange juice.

Wrap the dough in plastic wrap and chill for 30 minutes in the fridge.

Preheat the oven to 350F (175C).

In the meantime prepare the royal icing by beating the aquafaba with a hand mixer until you have stiff peaks, add gradually the icing sugar, until you have thick and glossy peaks. Cover and store in fridge until the cookies are ready.

Remove the cookie dough from the fridge and roll out on a floured surface or between two sheets of parchment paper to 1/4″ thickness and use cookie cutters to cut out shapes and transfer to baking sheets.

Place the cookies in the fridge for another 10 minutes.

Bake one sheet at a time on the middle rack for 10-12 minutes. Remove from the oven and let them cool 5 minutes before transferring to a wire rack to finish cooling.

Once the cookies are completely cooled, use the royal icing to decorate.

It takes about 1 hour for the royal icing to set.