Dice the frozen butter. Combine with flour and salt in food processor. Blend on low until butter is in small pea size pieces.
Add 2 tbs/30ml cream with ¼ c/60ml ice water. Process until a shaggy mass forms. If there is still a lot of loose flour, add more ice water 1 tbs at a time.
Bring pastry together in a thick disk. Wrap in cling film and chill in the fridge for at least 30 minutes.
Roll pastry out to a ¼”/6mm thick circle. Line a standard pie pan, trim and crimp the edge.
Prick the base a few times with a fork. Return to the fridge and chill for at least 15 minutes.
Preheat the oven to 350°F/180 C.
Slice bananas into ¼ - ½” slices.
Whisk the sugar, eggs, vanilla, nutmeg, and cornstarch in a large bowl until pale ribbons form.
Heat the milk and cream in a small saucepan until barely simmering. Remove from heat.
Whisk about 1/3 of milk mixture into the eggs. Pour the warmed egg mixture into the hot milk and stir to combine.
Layer the banana slices in the pastry case. Pour the custard over the bananas and make sure everything is level.
Bake for 50-55 minutes until the custard is just firm in the center, jiggling slightly when tilted, but not moving.
Allow to cool completely before serving.
Can be stored covered in the fridge for up to 3 days.