Place frost-proof bowls for crème brûlée in the freezer.
In a large mixing bowl, mix vanilla sugar, granulated sugar, and egg yolks well.
In a large pot heat up sea buckthorn juice together with heavy cream. Place a cooking thermometer in the pot and whisk regularly. When the temperature reaches 190 degrees Fahrenheit (90 degrees Celsius), remove the pot from heat.
Pour the hot heavy cream/sea buckthorn mixture little by little into the sugar/egg yolk mixture while whisking.
Pour back the crème brûlée mixture into the pot and heat it up while constantly whisking. When the temperature reaches 175 degrees Fahrenheit (80 degrees Celsius), remove the pot from heat.
Let it cool for about half an hour on the stove.
Preheat the oven to 230 degrees Fahrenheit (110 degrees Celsius).
Take out the frozen crème brûlée bowls and pour the mixture into the bowls.
Bake the crème brûlée for about an hour.
Place the crème brûlée in the fridge and allow it to cool completely.
When serving the dessert, take out the crème brûlée from the fridge and spread out an even, thin layer of granulated sugar on top of the crème brûlée. Use a kitchen torch to caramelize the sugar layer.