Amazing Rainbow Cake

For my last birthday I made a rainbow cake which was a huge hit with my guests. Since my party a few of my friends have asked me how I made the cake so I decided I would share it here today.
There are plenty of different receipes on the net but this one I found worked really well, was easy to follow and tasted great.

What I feel is the most important aspect of this cake, is it's frosted in white buttercream. Why? Because the smooth white exterior makes the cake look completely normal, but once you slice into it you realize... OH SNAP! THIS CAKE IS CRAZY! The buttercream frosting has a meringue like consistence which gives the cake that extra specialness. Its the yummy icing often used on fancy wedding cakes.

You will need:

226g butter, room temp

426 g sugar

5 egg whites, room temp

2 teaspoons vanilla

426 g flour

4 tsp baking powder

½ tsp salt

355 ml milk, warmed for 30 sec in microwave to bring to room temp

Red, orange, yellow, green, blue and purple GEL food coloring. Liquid will not be vibrant enough! (although if you can't find the gel the liquid will still work)

Making the cake:

Preheat the oven to 350F degrees. Oil and line how ever many 9” cake pans you have (I have three and I just reused them).

Sift together the flour, baking powder and salt. Set aside.

Cream the sugar and butter, then add the egg whites (I cracked them all into one bowl) and add them a little at a time. Add the vanilla and mix until fully incorporated. Then, alternating between wet and dry, add the milk and flour mixture in two parts.

Divide the batter evenly amongst 6 bowls, and then whisk a fair amount of the appropriate food color into each bowl. Keep in mind that the color of the unbaked batter will be the color of the baked batter. Pour into the pans and bake for 15 minutes each.

When you remove them from the oven, let them rest on the cooling rack, in the pan, for ten minutes. Then flip, cover, and stash them in the fridge to cool quickly.

If you don't have enough tins for all colours, you will just need to wait till you have cooked your first batch of colours and then re oil and line your tins to use again for the next batch of colours.

Lemony Swiss Meringue Buttercream

9 egg whites

350 g sugar

452 g butter, room temp

2 tsp lemon extract (optional)

Cook the egg whites and sugar in a small saucepan over medium heat, whisking constantly, until the sugar is completely dissolved (test by rubbing some between your fingers. If it's completely smooth, it's done). Pour into another bowl (an electric mixer is preferable) and whip on high speed until room temp. Then, on a medium-slow speed, add the butter, waiting until each piece is completely incorporated before adding the next. After all the butter has been added, turn the mixer back to high speed and whip until it has come together, about five minutes. Add the extract, beat briefly and then use.

If the buttercream seems soupy after all of the butter is added and does not come together after whipping, refrigerate for 5 to 7 minutes and continue whipping until it becomes fluffy and workable.

Assembly

Stack the layers in your preferred order smoothing frosting inbetween each layer as you go. Once each layer is stacked with frosting inbeteen each one, cover the outside of cake with remaining frosting.

This cake is a huge hit for any special occasion, not not try it for not your next celebration.