Position oven rack to the middle. Preheat oven to 350° F (177°C). Prepare two 8-inch round cake pans with parchment rounds, and grease the sides. Set aside.
In a large bowl, sift the flour, baking powder, baking soda and salt and whisk to combine. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a hand mixer, beat the butter, sugar, sour cream, vegetable oil and vanilla on medium-high speed until light and fluffy, about 4 minutes.
Scrape down the sides and bottom of the bowl. Lower the speed to medium-low and mix in the egg whites, one at a time until just combined.
Add ⅓ of the dry ingredients and beat just until combined, then add ½ of the buttermilk and mix until just combined. Continue mixing in ½ of the remaining dry ingredients, remaining buttermilk, then remaining dry ingredients. Remember to mix after each addition before adding the next.
Divide batter between 3 bowls and tint them red, yellow and orange using gel food colouring.
Using 3 ice cream scoops or spoons, divide the batter between the two pans, alternating with a dollop of each colour. Use a small offset spatula to carefully spread the batter into an even layer.
Bake for 30-35 minutes or until a toothpick inserted into the center comes out with a few moist crumbs.
Remove cakes from oven and allow to cool in pans for about 10 minutes, then turn onto cooling racks to cool completely.
FOR THE ICE CAKE LAYERS:
Repeat the same steps above for the ice cake layers, except tint the batter blue, light blue and leave the third portion plain.
FOR THE CANDY MELT FLAMES:
[SEE NOTES] Line a large baking sheet with wax paper. Set aside.
Add the red, yellow and orange candy melts to three separate heat safe bowls. Microwave each bowl one at a time in 30 second intervals until candy melts are completely melted and smooth.
Dip the tip of a small offset spatula into the red candy melts and swipe a small amount onto the wax paper lined baking sheet in an upwards motion. This is the bottom of the flame. Make a few rows of this, I used about 20 flames around my cake but it’s best to make as much as you can so you have extra just incase any break.
Without cleaning the spatula, repeat the same swiping motion using the orange candy melts. Make sure the orange is touching the top of the red stroke so they could blend in the middle.
Repeat with the yellow candy melts, except this time don’t swipe. Just add a touch of yellow to the top.
Then use a toothpick to swirl the colours together and pull the top part up to create a flame shape. It’s important to work quickly because once the candy melts set, you won’t be able to do this. Allow to set at room temperature for about 30 minutes to an hour.
FOR THE ICE SHARDS:
Line a baking sheet with wax paper or parchment paper. Melt the white and blue candy melts in separate bowls.
Pour the blue candy melts over the entire sheet, then pour on the white candy melts.
Using a small offset spatula, spread the candy melts into a large rectangle, allowing the colours to slightly blend together. Allow to set at room temperature for about 30 minutes to an hour.
