Use an electric hand mixer to combine the flour, cream cheese and butter. Work dough with hands to form in to a ball and then flatten it a little into a disc. Wrap with plastic wrap and refrigerate for at least an hour.
Preheat oven to 350 degrees F. Coat mini muffin pan(s) with non-stick cooking spray.
Remove chilled dough from refrigerator and divide it into 24 evenly sized balls. Place each ball into a cup in the muffin pan and pat into shape with your fingers.
In a medium mixing bowl, use an electric hand mixer to combine egg, brown sugar, salt, and vanilla. Use a spoon to stir in melted butter and pecans. Place a small amount of the filling in each pastry lined muffin cup; dividing it evenly between the 24 cups.
Bake for 20 minutes or until nicely browned and set. Remove from oven and allow to cool in muffin pan(s) for 10 to 15 minutes then use a fork or small sharp knife to pop the tarts out. Allow them to cool completely and store in an airtight container.