Make the dough
Put all the spices and ammonium bicarbonate in a bowl and set aside. Using a sharp knife cut candied fruits into small pieces. Crack eggs in a bowl and lightly beat them. Grind down the croissant in food processor or crush them by hands. If your croissants are not well dry, simply toast them in the oven. Combine all the ingredients in a bowl, except water and spices. Add water little by little and in between add the spices. Mix all the ingredients very well and let stand for about 30 minutes.
In the meantime if you're using almonds with skin for decoration, put them in a cup or a bowl and pour hot water over them. Let them soak for about 10 minutes. Drain the almonds and squeeze them one by one with your hands to remove the skin. Using a knife split the almonds into halves. Then preheat the oven to 180 °C (356 °F), with both top and down heat.
Two baking sheets are for baking, two to arrange glazed cookies and one you'll use it to cool the cookies before glaze.
Shape and bake gingerbread cookies
Line a baking sheet with a parchment paper and arrange oblaten on it. After 30 minutes fill a cup with water. Wet your pointing finger on the left hand. Using a spoon scoop a bit of the mixture and put it on the oblate with the help of your wet finger. Dip the second spoon in the cup with water and flatten the dough on the oblate. Arrange almond halves on the flattened cookies and bake 30 minutes. You only add almonds before baking to cookies that you'll be coating with icing sugar. The ones that you'll be coating with chocolate, you'll add the almonds on them after baking and brushing them with chocolate.
While the first baking sheet is in the oven, prepare the second baking sheet and melt the chocolate over a hot bath or in the microwave. In a separate bowl mix icing sugar with lemon juice or rum. After 30 minutes remove the baking sheet from the oven. Using a slotted spoon or a pizza cutter transfer the cookies to one of the three remaining baking sheets and let cool. Bake the next cookies. While the next baking sheet is in the oven arrange Oblaten on the baking sheet that you've just used to bake the first gingerbread cookies, scoop the dough flatten it and bake when the oven is empty. Repeat the process until you have used up all the dough.
Glaze gingerbread cookies and let cool
Using a pastry brush the baked and cooled cookies (with almonds) with icing sugar. Brush the cookies that you have baked without almonds with chocolate and decorate them with almonds. Put the cookies on the two remaining baking sheets and let dry and cool completely overnight at room temperature. Otherwise your gingerbread cookies will become molded if you store them immediately, without giving them enough time to dry.
How to store gingerbread cookies