Whisk together flour and salt until well combined. Cut in cold, unsalted butter until the mixture resembles coarse crumbs. Gradually add ice water until the dough holds together. Wrap in plastic and refrigerate for at least 30 minutes.

In a medium saucepan, melt unsalted butter over medium heat, stirring frequently, until golden brown and nutty, about 5-8 minutes. Remove from heat and let cool slightly.

In a large bowl, whisk together eggs and vanilla, then slowly mix in warm brown butter and light brown sugar until smooth.

Preheat the oven to 375°F (190°C). Roll out the chilled pie crust to fit a 9-inch pie dish. Transfer and press into the dish. Prick with a fork and freeze for 15 minutes.

Sprinkle pecans evenly in the crust, pour the filling over until just below the crust edge, and bake for 50-60 minutes until center is slightly jiggly.

Cool completely at room temperature on a wire rack before slicing and serving.