Preheat oven to 375°F (190°C). In a mixing bowl, combine all-purpose flour, unsalted butter, sugar, and salt until crumbly. Add egg yolk and ice water to form dough.

Roll the dough into a 12-inch circle and place in a 9-inch pie pan. Prick bottom with a fork, cover with parchment and weights, and bake for 15 minutes. Remove weights and bake for another 10 minutes until golden.

In a medium saucepan, combine whole milk and heavy cream, stirring in sugar. Bring to a simmer, then cool slightly.

Whisk together eggs, vanilla extract, ground cinnamon, and nutmeg in a large bowl. Slowly combine warm milk mixture, whisking constantly to prevent curdling.

Pour custard into pre-baked pie crust and bake at 350°F (175°C) for 40-45 minutes until center jiggles slightly.

Cool at room temperature for 30 minutes, then refrigerate for at least 2 hours before serving.

Serve slices with whipped cream and a sprinkle of cinnamon on top.