Start by making your tart crust. Then place the dough in the refrigerator for 1 hour to chill. Proceed to the next step.
Roll out dough on a lightly floured surface into a large circle ⅛ inch thick, then place the dough into a 9 - inch lightly greased tart pan with removable bottom. Press the dough with your hands on the bottom and sides of your pan, crimping the sides of the pan, smoothing out any gaps or cracks. Then pop the tart pan in the freezer while you make the filling.
Add the chocolate chips and butter to a large glass bowl and microwave for 30-second intervals, stirring in between with a spoon, until melted. It should take around 1 minute to fully melt. Then add the dark brown sugar, eggs, vanilla extract, and salt to the melted butter and chocolate mixture. Stir until well combined.
Remove the tart pan from the freezer and carefully pour the filling into the pan.
Arrange 3 rows of pecans on top of the tart with one nut reserved for the center in a circular pattern and evenly spaced. Then place the tart on a large baking sheet and into the oven for 20 minutes. After 20 minutes remove the tart from the oven and place a sheet of aluminum foil over the top, to avoid the pecans from burning. Return the tart to the oven for 3-5 more minutes. The pecan tart is ready once the middle has set and the tops of the pecans are golden brown.
Remove the tart from the oven and allow it to cool on a wire rack at room temperature for 4 hours before serving. Once the tart has cooled, place a sheet of aluminum foil over the top and store it at room temperature. For best results, serve the tart the next day.