In a large pot, beat egg yolks together with sugar and salt until fluffy. When thoroughly combined, add a little of the milk at a time, whisking until fully incorporated and smooth – you don’t want any unblended chunks of egg mixture. Add remaining milk and heavy cream, whisk until well combined. Heat just to the boiling point, whisking constantly. Once mixture begins to boil, remove from heat.
Divide mixture out evenly into three glass bowls, allow to cool to room temperature
Once cooled, use food colouring to tint the mixture in one bowl yellow, another blue, and the third purple.
Add 1/4 tsp Banana Cream flavour oil to the yellow mixture, 1/4 tsp Bubble Gum flavour oil to the blue mixture, and 3/4 tsp Grape flavour to the purple mixture. Stir each well, rinsing the spoon off between flavours. Cover all bowls and transfer to fridge to chill overnight.
Prepare yellow ice cream according to your ice cream maker’s instructions. Once it reaches a good thick ice cream texture, transfer back to the bowl and freeze. Allow ice cream maker to refreeze for another 2 hours, or – ideally – overnight.
Prepare blue ice cream according to your ice cream maker’s instructions. Once it reaches a good thick ice cream texture, transfer back to the bowl and freeze. Allow ice cream maker to refreeze for another 2 hours or – ideally – overnight.
Prepare purple ice cream according to your ice cream maker’s instructions. As it approaches the frozen stage, remove the yellow blue ice cream from the freezer.
Scoop random balls of yellow and blue ice creams into a freezer-safe dish that will hold 2L of finished ice cream. Ladle some mostly-frozen purple ice cream all over it, allowing it to flow into any crevices. Press mixture down slightly to eliminate any air holes.
Scoop more yellow and blue ice cream in, top with more purple and repeat until all of the yellow, blue, and purple ice cream is in the final container. Cover and freeze until firm.
Alternately: If that sounds like too much work – or too many dishes to wash, just layer the flavours into the final freezer container, as they come out of the ice cream maker. Just be sure to dig deep when scooping!