Wrap 1 small washed beetroot in foil and bake for 1 hour at 375F. Remove from the oven, cool to room temperature.
Peel the beetroot, cut it in small chunks and whizz in a blender until very finely ground. Measure out 1/2cup of the beet mixture (you won't need the leftovers) and whizz in a blender once again but this time with a small addition of milk until purée like.
Dissolve the cornstarch in 50ml whole milk, leave to rest.
In a small saucepan combine the leftover whole milk, the heavy cream, sugar, agave syrup, pinch of salt and zest of 1 orange, mix, heat until boiling. Take off heat, cover with a lid and leave to rest for 10min. Strain through a sieve, return the mixture into the saucepan, heat once again until almost boiling. Add the cornstarch milk and cook on medium stirring constantly until thickened. Take off heat, mix in 50gr cream cheese and the beet purée until smooth and combined. Cool to room temperature and if willing whizz the custard in a blender once again for a smoother texture. Transfer to the fridge overnight.
Freeze in your ice cream maker according to the manufacturer's instructions. Store in an airtight container in the freezer or spoon right away. Pair with a dark chocolate beetroot ice cream.