Rainbow cake is a visually striking, multi-layered cake known for its vibrant, colorful appearance. Each layer of the cake is made with a different color of the rainbow, typically achieved by incorporating food coloring into the batter. The result is a cake that, when sliced, reveals a brilliant spectrum of colors that are both fun and festive.

Why It’s So Popular:

1. Visually Stunning: The most striking feature of rainbow cake is, of course, its color. The bold, layered effect creates a sense of excitement and fun, making it a perfect centerpiece for parties and celebrations.
2. Versatility: While the classic rainbow cake uses six layers (one for each color of the rainbow), you can adjust the colors and number of layers based on personal preference. Some bakers also incorporate various types of fillings and frostings to enhance the flavor and texture.

Here’s a simple recipe for a layered rainbow cake with a fluffy, creamy frosting to tie everything together.

🌈 Easy 6-Layer Rainbow Cake

🎂 Ingredients

Cake Batter

• 4 cups cake flour
• 3 tsp baking powder
• ½ tsp salt
• 1½ cups unsalted butter (room temp)
• 2½ cups white sugar
• 6 large eggs (room temp)
• 1½ cups milk (room temp)
• 2 tsp vanilla extract
• Gel food colouring (red, orange, yellow, green, blue, purple)

👉 Use gel colouring, not liquid — it keeps colours bright without thinning the batter.

🧁 Buttercream Frosting

• 2 cups unsalted butter (room temp)
• 6–8 cups icing sugar (sifted)
• 2–4 tbsp milk or cream
• 2 tsp vanilla extract
• Pinch of salt

👩‍🍳 Method

1️⃣ Prepare

• Preheat oven to 180°C.
• Grease and line 6 x 20cm round tins.
  (If you only have 2–3 tins, bake in batches.)

2️⃣ Make the Batter

1. Sift flour, baking powder and salt together.
2. Cream butter and sugar until light and fluffy (3–5 minutes).
3. Add eggs one at a time, mixing well after each.
4. Add vanilla.
5. Alternate adding dry ingredients and milk:
   • Flour → Milk → Flour → Milk → Flour
6. Mix just until smooth.

3️⃣ Colour the Batter

1. Divide batter evenly into 6 bowls.
2. Add gel colouring to each bowl.
3. Mix gently until evenly coloured.

Try to keep layer amounts equal — you can weigh them for precision.

4️⃣ Bake

• Spread each colour evenly into its tin.
• Bake 15–20 minutes (layers are thin).
• Insert skewer — if it comes out clean, it’s done.
• Cool completely before frosting.

🧁 Buttercream

1. Beat butter until pale and creamy.
2. Add icing sugar gradually.
3. Add vanilla and salt.
4. Add milk 1 tbsp at a time until smooth.
5. Beat 3–5 minutes until fluffy.

🎂 Assembly

1. Level layers if needed.
2. Stack in rainbow order:
   Purple → Blue → Green → Yellow → Orange → Red
   (Or reverse if preferred.)
3. Spread thin layer of buttercream between each layer.
4. Apply crumb coat (thin layer all over cake).
5. Chill 20–30 minutes.
6. Apply final smooth coat of buttercream.

Decorate with sprinkles, piping, or leave smooth and white for a surprise rainbow inside.

💡 Helpful Tips

✔ Don’t overbake — thin layers dry quickly.
✔ Chill between frosting stages for clean edges.
✔ Use a serrated knife to level layers neatly.
✔ Clean knife between slices for perfect rainbow reveal.