Cut cream cheese and butter into 1-inch cubes and place in food processor or electric mixer, beating to combine well. If you use the food processor, turn mixture out into a large mixing bowl. Add flour a little at a time, incorporating with a wooden spoon until mixture gets so stiff you cannot work it in. Then use your well-scrubbed fingers.
Form dough into a ball, dust with flour and wrap well in plastic wrap. Refrigerate 2-3 hours.
Remove dough from refrigerator and form into 1-inch balls. Press balls into 1 1/2-inch wide ungreased muffin tins to form small tart shells. Set aside.
Preheat oven to 350 degrees.
Combine melted butter with eggs, sugar, salt, vanilla and pecans. Fill each dough-lined muffin tin with about 1 teaspoon of filling mixture. Bake 25 minutes, or until crust turns golden brown and filling has set. Remove pans from oven and let tassies rest for 20 minutes, then remove to a rack to continue cooling.