Cupcakes

1. Preheat your oven to 350°F (180 °C).
2. Line a 12-cup muffin tin with paper liners. I don’t skip liners here because the colors stay prettier and nothing sticks.
3. In a medium bowl, whisk together 1 cup cake flour, 1 1/2 tsp baking powder, and 1/4 tsp salt. Set that aside.
4. In a large bowl, whisk 1/2 cup sugar and 2 large eggs for about 1 minute until slightly pale and smooth.
5. Add 1/2 cup vegetable oil (or melted butter), 1/2 cup buttermilk, and 1 tsp vanilla extract. Whisk until fully combined.
6. Add the dry ingredients to the wet mixture and gently stir just until combined. Don’t overmix. A few tiny lumps are fine.
7. Overmixing makes cupcakes dense, and we want them soft and fluffy.
8. Divide the batter evenly into 5 small bowls. Each bowl should have just over 1/3 cup, roughly 6 tbsp per bowl. 
9. Tint each bowl with food colouring. Add about 1/2 tsp colouring to each bowl and mix well so there are no streaks.
10. You’ll need to mix red and yellow together to make orange. Add a little at a time until you get bright, bold colors. Pale batter bakes up lighter than you think.
11. Using small spoons or a small cookie scoop, layer the batter into the lined muffin cups.
12. Start with blue, then green, then yellow, then orange, and finish with red.
13. Add about 1 tbsp of each color per layer. Don’t spread the batter. It will level out on its own as it bakes.
14. Fill each liner about 2/3 full. If they’re too full, they’ll dome and spill over.
15. Bake for 15 to 18 minutes, or until a toothpick inserted in the center comes out clean.
16. The tops should spring back lightly when touched.
17. Let the cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely before frosting. If they’re even slightly warm, the buttercream will melt. 

Quick Buttercream Frosting

1. In a large bowl, beat 1/2 cup room temperature butter until smooth and creamy, about 2 minutes.
2. Add 3 tbsp milk and 1 tsp vanilla extract, and mix again.
3. Gradually beat in 2 1/2 to 3 cups sifted icing sugar, about 1/2 cup at a time, until the frosting is thick and spreadable.
4. If it’s too thick, add a splash of milk. If it’s too soft, add a little more icing sugar.
5. Beat for another 1 to 2 minutes until light and fluffy.
6. Pipe or spread onto completely cooled cupcakes.
7. Add sprinkles if you’re feeling extra.