Preheat the oven to 325°F. Lightly spritz the bottom of a 9-inch tart pan with a removable bottom or regular metal pie pan with cooking spray. Set aside.
In a medium-size mixing bowl mix together the flour and brown sugar.
Using a pastry blender or 2 forks, cut the cold butter into the flour until it resembles peas.
Mix-in the chopped pecans, toffee bits and vanilla.
Press firmly and evenly into the pan.
Using a sharp knife or pastry wheel score the top into 16 wedges. (This helps with pecan placement)
Gently press one whole pecan onto the outer end of each wedge.
Bake for 28-30 minutes until lightly golden.
Remove from the oven and rest on a cooling rack. Allow to cool and set for 30 minutes.
Remove the outer ring and use a long sharp knife to carefully cut into wedges while still warm.
Store in a container tightly sealed at room temperature.