In a mixing bowl add flour, baking powder, baking soda, salt. Sift them in a sieve so all ingredients get incorporated.
In another mixing bowl add oil, buttermilk, vanilla essence, sugar and color whisk it will till sugar melts.
Now mix the dry and wet ingredients together and pour in the greased (greased with butter and dusted with flour or lined with parchment paper) baking tin and place it in the preheated oven (which was preheated for 10 minutes at 180 degree) and bake it for 15 minutes.
After baking seven layers trim or level up each sponge cake so that they can be stacked upon.
For butter frosting in a huge mixing bowl add butter and with an electric beater beat the butter until soft and fluffy. Gradually add icing sugar and vanilla essense and beat for 15 minutes till soft peaks.
Place the first sponge cake on a rotating cake table above a cake cardboard , apply some frosting over card board and place it. Now apply frosting (with piping bag )on first layer spread evenly then place next layer and apply frosting on it and spread repeat till all seven layers. When the last layer is placed apply good amount of frosting on the cake and rotate the table spreading evenly the butter frosting all over with help of spatula or frosting knife.
Decorate your cake with gems or rainbow confetti balls.
