For the Tart Dough  

Cream together the butter, sugar, salt and vanilla.Add the eggs one at a time and beat well between additions.Add the flour and blend into soft dough. Wrap the dough in plastic wrap and flatten out. Chill until firm before use.Roll out the dough and fit it into a 10 inch tart pan. Blind bake in a 375 degree oven for 15-18 minutes. 

For the Maple Walnut Tart Filling

 Cream together the butter, sugar, and salt on second speed of mixer.  Scrape down the sides of the bowl.Add the eggs one at a time, scraping the bowl halfway through, until fully incorporated.On lowest speed, add the maple syrup, corn syrup and vanilla and mix, then add walnuts and mix thoroughly.Pour into prepared tart shell and bake in a 375 degree oven for 12 minutes. Rotate, and bake 12 minutes. Remove from the oven and let cool to room temperature.