In a large mixing bowl, whisk egg yolks, sugar, and vanilla powder for 2 minutes.
In a large pot, pour heavy cream and whole milk. Slowly heat up until it reaches 175 degrees Fahrenheit (80 degrees Celsius) while stirring.
Remove the pot from heat and add the egg yolk/sugar mixture.
Bring back the pot and slowly heat up to 175 degrees Fahrenheit (80 degrees Celsius) again. It is important not to let it boil.
Let the ice cream base cool in the fridge for 3 hours. Meanwhile, make the bilberry/blueberry mixture.
Bilberry/Blueberry mixture
Place bilberries/blueberries, sugar, and 1 tablespoon of water in a small pot. Slowly bring to a boil and let simmer for 5 minutes. Remove from heat.
Place in Ice Cream Machine
When the ice cream base has cooled for 3 hours, take it out of the fridge. Turn on your ice cream machine and pour in the ice cream base and the bilberry/blueberry mixture. There is no need to mix it before it goes into the machine.
After 15-30 minutes the bilberry/blueberry ice cream is done and can either be eaten right away or placed in the freezer for further freezing.