Step 1: Bake the Cake

1. Preheat oven to 350°F (175°C) and grease three 6-inch or 8-inch cake pans.
2. In a bowl, whisk together flour, baking powder, baking soda, and salt.
3. In another bowl, beat butter and sugar until light and fluffy. Add eggs one at a time, then mix in vanilla extract.
4. Alternate adding dry ingredients and milk, mixing until smooth.
5. Divide batter into three bowls and add gel food coloring to each for pastel cake layers.
6. Pour batter into cake pans and bake for 25-30 minutes, or until a toothpick inserted comes out clean.
7. Let cakes cool completely before frosting.

Step 2: Make the Buttercream

1. Beat butter until creamy, then gradually add powdered sugar.
2. Mix in heavy cream and vanilla extract, beating until smooth.
3. Divide frosting into bowls, tint with pastel gel colors, and transfer to piping bags with star tips.

Step 3: Assemble & Decorate

1. Stack cake layers with a thin layer of buttercream in between.
2. Apply a crumb coat, chill for 30 minutes, then frost smoothly.
3. Pipe swirls and rosettes to create the unicorn’s mane.
4. Shape fondant ears and a horn, paint them gold, and attach to the cake.
5. Draw unicorn eyes with an edible marker or use fondant.
6. Add pearls, sprinkles, and edible glitter for extra magic.