To make crust cream together cream cheese, butter, and flour until it forms a dough. Wrap in plastic wrap and chill in the fridge for one hour.
Once chilled, shape dough into 1 inch dough balls and press evenly into a greased mini muffin pan. Make sure to press against the bottom and sides. Set aside and make filling.
To make filling, beat together egg, brown sugar, 1 tablespoon of butter, vanilla, and salt. Divide pecans evenly into each pastry cup. Using a spoon, divide egg mixture into each pastry cup over the pecans. About 1 teaspoon each. Place into the fridge to chill while your oven preheats. Preheat your oven to 325 °F (163 °C).
Once the oven is preheated, bake tassies for 25 minutes until filling is set. Allow to cool for 15 minutes before removing them from the pan.