Roll out the pie crust into a round circle. You will just want to roll it out a little bit wider than it already is. Using your cookie cutter, or biscuit cutter, cut out 24 circles. You may need to re-roll the dough to use all of the dough and to get the 24 you need.
Stretch out the dough a little bit with your fingers and place the circles into the mini muffin pan. Place the muffin pan into the fridge while you are preparing the filling to keep the dough cold.
In a medium-sized bowl, add the egg, corn syrup, brown sugar, butter, salt, and vanilla.
Once the filling is ready, remove the muffin tin from the fridge, and using a cookie scoop or teaspoon, spoon the filling into each tart. Only fill the tart about ½ full. You will be tempted to fill it fuller, however, do not. You will still need to add the pecans plus the pie crust is going to expand. This will help prevent everything from overflowing out of the pan.
Once you have filled all of the tarts, top each of them with the pecans. You can add more or less of the chopped pecans. It’s honestly up to you
Then place the Butter Tarts into the air fryer and bake for 12 to 15 minutes at 330 degrees F. Remove when the crust is golden brown.
Let them cool and then carefully remove them with a knife from the pan. Enjoy warm and with a dollop of vanilla ice cream or whipped cream. My family enjoyed them also as a breakfast treat the next morning.