Preheat the oven to 350 degrees F. Prepare mini muffin pans by greasing cups if it is not a nonstick pan; set aside.
To make the dough, beat together the butter, cream cheese and flour on low speed of a stand or hand mixer until all of the flour is incorporated. Divide the dough into 48 pieces and roll into balls. Place on a plate or in a zip-top bag and refrigerate for about an hour.
Either press the dough balls into the muffin cups and up the sides, or flatten the balls slightly with your palm and use a rolling pin to roll into a disk about 2-3 inches in diameter (a little larger than the size of the muffin cup opening) and place into the muffin cups.
To make the filling, mix together the brown sugar, chopped pecans, eggs, melted butter and vanilla extra with a spoon and then evenly divide it between the dough-lined mini muffin cups. Top each with some additional chopped pecans.
Bake for 20 to 25 minutes or until the tops are set. Cool for a few minutes in the muffin cups and then remove to a cooling rack to cool completely. The tassies can be stored in an airtight container at room temperature.