Put the flour, butter, and brown sugar into a food processor. Process until the butter is cut in and crumbs form. (Alternatively, you can cut in the butter by hand).
Stir ⅓ cup of the chocolate chips into the crumbs.
Press into the bottom of a 9x13 pan.
Bake the crust for 14-16 minutes or until light golden brown.
Combine the condensed milk, egg, vanilla, and salt in the food processor.
Process until smooth. (Or mix well in a large bowl).
Mix in the chocolate chips.
Spread on top of the crust.
Bake for 25 minutes. Cool completely. Cut into bars.