Preheat oven to 375°F (190°C). Cream butter and brown sugar until fluffy. Add egg yolk and vanilla, mix well. Gradually add oats, flour, and salt to form dough. Press into a 9-inch pie plate and chill for 30 minutes.

Par-bake the crust for 12-15 minutes until lightly golden and firm. Let it cool completely.

In a saucepan, combine milk and cream. Warm until bubbles form but do not boil.

Whisk together eggs and sugar until pale. Stir in vanilla and spices. Slowly pour in hot milk mixture while whisking constantly.

Strain the custard mixture into the cooled crust to ensure smoothness.

Bake the pie at 325°F (160°C) for 40-50 minutes until set with a slight jiggle.

Cool the pie on a wire rack for 2 hours, then refrigerate for at least 4 hours or overnight.

For praline sauce, combine pecans, brown sugar, corn syrup, and butter until smooth. Stir in cream and vanilla, let cool.

Serve the pie chilled or at room temperature, drizzling with praline sauce if desired.