Rainbow Cake

First.
First entry, first day attempt of making rainbow cake.

Taking recipes from several blogs, now lets see if the look is marketable:

Took recipe from http://ajwinajeera.blogspot.com/2012/03/rainbow-cake.html
But, according to husband, the taste is fine, but the texture got problems:
1) The cake is slightly hard
2) The buttercream is slightly sandy... (what? I used icing, not granulated sugar. But... I didn't sift it.. kena sift ke? ha ha ha)

Ok.. Next time (bila ntah) buat lagi, betulkan texture. I wonder what should I amend? the recipe or the way I beat the batter? kenapa dia keras ek? takdela keras sgt, cuma tak lembut mcm sponge cake.