How to Make It
Make Dough: Place 1/2 cup pecans in a food processor and blitz until finely ground. Set aside. In a bowl, beat together butter and cream cheese until fully incorporated. Add flour and ground pecans and mix until a shaggy dough forms. Use your hands to press the dough into a solid mass. Cover with plastic wrap and refrigerate for 1 hour.
Preheat oven to 350°F. Grease a 24-cup mini muffin pan with cooking spray. Scoop 1 tablespoon of dough into each muffin cup. Use your fingers to evenly press dough into the bottom and up the sides of each muffin cup. Transfer muffin tin to freezer while making the Filling.
Make Filling: Whisk together egg, brown sugar, maple syrup, vanilla, salt, and bourbon until sugar is dissolved and mixture is homogenous. Remove muffin tray from freezer. Place 1 teaspoon of chopped pecans in each of the muffin cups. Pour the Filling over the pecans until it almost completely fills the pastry cups. Bake until the filling has puffed and the pastry has lightly browned, 20 to 24 minutes. Allow to cool before removing pecan tassies from muffin pan with an offset spatula.