Start with peeling and chopping the potatoes then boil them for around 15 min. Turn on the oven to 225°C (435°F)
When potatoes are boiling you can prepare the pie crust by first mixing all dry ingredients and then add butter in chopped pieces. Mix it with your hands until mixture resembles course meal.
Use a hand mixer with dough hooks and add the cold water a tbsp at a time. The mixture is ready once it holds together.
Spread out plastic wrap and press out the dough into a disc. Wrap the plastic around it and place in the fridge for a while.
The potatoes should be ready by now so drain and mash together with the brown sugar.
Optional step: Take a baking sheet and line with parchment paper before spreading out the mashed potato and roast in the oven until it starts to brown, then let it cool a bit. Lower the heat of the oven to 175°C (350°F)
Mix the remaining ingredients for the filling with an immersion blender then add the cooled potato mixtue (to avoid coagulation of eggs) and mix again until you have a very smooth filling.
Press out the dough in a pie form and add the filling
Bake in oven at 175°C (350°F) for around 45 min, then let it cool before serving together with whipped cream or vanilla icecream