Carrot cake: Mix the butter and the crushed walnuts in a sauce pan and warm slightly until butter softens. Set aside. Beat the sugar and the eggs with a mixer until it starts forming bubbles. In another bowl, mix the almond flour, baking powder, salt and flour. Blend with egg and sugar mixture until no lumps remain. Add the butter mixture, grated carrots, Maille(R) Old Style mustard, crushed walnuts, raisins, citrus fruit zests, cinnamon, ginger and chopped grains of coriander and mix everything carefully together. Divide mixture into small silicone cooking molds.
Cook in a 375 degrees F oven for 15 minutes (depending on the size of the cake molds). Once cooked, remove the cakes from the molds and let them cool down all the way.
Icing: Mix all the ingredients together. Cover the mini carrot cakes with icing and let them harden for 2 hours in the open air.