Position rack in lower third of oven. Preheat oven to 425 degrees and set cookie sheet on rack to get hot.
Line 9-inch pie plate with crust. Line crust with foil and fill with pie weights. Place on cookie sheet in oven. Prebake crust 15-20 minutes.
Remove cookie sheet with pie plate on it, gather up edges of foil with pie weights inside and lift out. Set aside pie shell.
Reduce oven temperature to 375 degrees at 5,000 feet, 325 degrees at 10,000 feet. Move oven rack to center of oven.
Melt butter in medium saucepan, then stir in brown sugar, corn syrup, molasses and salt. In cup, combine lemon juice and 1 teaspoon vanilla; stir in cornstarch until dissolved, then stir mixture into pan.
Bring to full, bubbling boil over medium-high heat, stirring constantly with wooden spoon, about 3 minutes. Stir down bubbles, then remove from heat. Stir in remaining vanilla. Whisk eggs in mixing bowl. While continuing to whisk, add a few tablespoons hot syrup to eggs, then whisk eggs into hot syrup, beating well as you do so (strain mixture if lumpy).
Pour hot filling into partially baked pastry shell and arrange nuts on top. Bake about 30 minutes, or until knife inserted in center comes out clean or coated with clear syrup.
Cool pie on wire rack and serve at room temperature.