This is the perfect summer celebration cake. We've got six layers of moist vanilla rainbow cake, swiss meringue buttercream, and M&M's. Delicious!
Pre-heat oven to 180ºC. Grease and line six 6-inch cake pans.
Whisk together flour, baking powder, and salt in a bowl.
In a mixing bowl, beat the butter and sugar until light and fluffy.
Add the vanilla. Then add eggs in four additions. Scraping down sides in between.
Pour in the flour mixture and mix until combined.
Divide the batter evenly in 6
Colour each bowl to match an M&M’S colour, red, blue, green, yellow and orange, and brown
Add each colour to a prepared pan. Bake for 15 minutes or until a toothpick inserted comes out clean. Let cool in the pans for 5 minutes before removing to a wire rack to cool completely. Then trim the tops of any bumps.
Once the cakes are cooled, trim the top if there are any bumps for a smooth flat top.
Bring a pot of water to a simmer and place a heatproof bowl on top. Add the egg whites and sugar to the bowl and whisk to combine. Cook this mixture over the bain-marie until the sugar is completely dissolved.
Transfer this to a stand mixer or a large mixing bowl. Whip until stiff peaks form then gradually add the butter bit by bit until incorporated and the buttercream is smooth.
Layer the cakes with the buttercream in between, topping with some M&M’s, leaving the top layer uncovered. Transfer to the fridge to set for 30 minutes.
Cover the cake in the buttercream and decorate the top with rings of M&M’S Chocolate
Chill in the fridge for 30 minutes before slicing and serving.