Line a cookie or baking sheet with parchment paper. Place a vase upside down in the middle. Remove cake from the freezer and place on top of the vase.
The mirror glaze needs to be 90°F / 32°C while glazing that it is not too thin and not too thick. Use a candy thermometer. When your glaze is too hot, let it stand until it cools down a bit. This will go very fast. Otherwise, the glaze doesn’t stick to your cake and is too runny. When the glaze is too cold, it is too sticky, and you can’t pour it over your cake. In this case, warm it up in the microwave for a few seconds.
Pour the blue from the first big bowl into the very dark space blue in the second big bowl. Give it a few gentle swirls and draw a pattern. Don't mix up the colors. Pour over cake beginning on the top and then let drip over the sides until the cake is fully glazed. Drip with a spoon a few lines of teal, purple, and pink on top. Go with the lines of the light and dark blue pattern.
Brush with a big offset spatula over the top of the cake to smooth the colors. Sprinkle a bit of black pearl dust and white food coloring on top of the cake with a brush.
Let dry for about ½ hour then transfer to the fridge and chill for 2 hours. Cut cake with a very warm knife (warm with hot water then dry) for best cutting results. Store leftovers in an airtight container in the fridge up to 3 days.