Place baking sheet on middle rack of oven. Preheat oven to 425° F.
Melt butter over medium heat in small saucepan. Cook, swirling occasionally, until foam subsides, the milk solids turn golden brown, and the butter smells nutty and toasty, approximately 5 minutes.
Add maple syrup and golden syrup to pan. Continue to cook, stirring occasionally, until the mixture thickens and reduces slightly, 2 to 3 minutes.
Remove from heat. Whisk in honey. Let cook at least 10 minutes.
While syrup cools, combine sugar, eggs, bourbon, vanilla, and salt in large mixing bowl.
Gradually pour system mixture into egg mixture, whisking constantly. With rubber spatula, scrape in brown bits from the bottom of the saucepan.
Mix egg yolk with about 1 tablespoon of cream, ½ and ½, or milk.
Remove crust from freezer. Place pecans in the bottom of the crust. Pour filling over pecans. Brush exposed crust with egg yolk mixture.
Place pie on baking sheet in oven. Bake 10 minutes, then reduce heat to 350° F. Bake until center of pie has puffed up and turned golden brown, approximately 35 to 45 minutes.
Transfer to cooling rack. Sprinkle with flaky sea salt. Let cool at least 2 hours. Serve warm or at room temperature.