In a skillet over medium heat toast the buckwheat kernels, stirring constantly as not to burn them. The kernels should develop a characteristic aroma that will infuse the ice cream later on. Take off heat and save 2tbsp kernels for later use.
Dissolve the cornstarch in 50ml whole milk, leave to rest.
In a small saucepan combine the leftover milk, heavy cream, sugar, buckwheat honey, a pinch of salt, seeds of 1 vanilla bean pod and the toasted buckwheat kernels, place on medium heat, bring to boil, cover and let sit for 2-3hours.
Sieve the milk mixture and return it back into the saucepan, bring to an almost boil, add the cornstarch milk and cook on medium constantly stirring until thickened. Take off heat, add the cream cheese, mix until smooth. Cool to room temperature, then transfer to the fridge overnight.
Churn the ice cream according to the manufacturer's instructions adding 2tbsp lightly crushed buckwheat kernels at the last minute of freezing. Store in an airtight container in the freezer or spoon right away.