preheat oven to 350 degrees (make sure rack is in the in the center of the oven) Lightly butter a 9-inch square pan.
You may or may not wish to line the baking pan with aluminum foil.
You would do this so that you could remove the whole brownie bake from the pan at once.
If you choose to do so, line it so that the foil extends approximately 2 inches beyond two opposite sides of the pan.
(and then lightly butter the foil)-- folding the overhang down along outside of the pan.
In the top of a double boiler set over hot, not simmering, water, melt the unsweetened chocolate with the butter, stirring frequently until smooth Remove the top part of the double boiler from the bottom and transfer the chocolate mixture to a large (preferably glass) bowl.
Let the chocolate mixture cool for about 10 minutes, or until tepid.
Add the sugar and salt to the chocolate mixture.
Using a hand-held electric mixer set at low speed, beat mixture for 15 to 20 seconds, until blended Scrape the bottom and side of the bowl with a rubber spatula and then beat in the corn syrup and the vanilla.
Add the eggs one at a time, beating for no longer than a few seconds after each With a rubber spatula, stir in the flour mixture Scrape the batter into the prepared pan and spread it evenly.
Add cream cheese to a medium size bowl, and beat with electric mixer on medium speed until smooth, Add sugar, mixing until blended.
Add egg and vanilla and mix just until blended.
Pour cream cheese mixture evenly over brownie mixture, and then cut through batter with knife several times for a marbled affect.
Bake for 30-40 minutes until cream cheese mixture is lightly browned.
Take a toothpick and stick through a corner that has no cream cheese.
If it comes clean, your brownies are done.
Do not overbake the brownies!
Cool brownies completely in pan set aside on a wire rack.
If you chose to line the pan with foil (so they could be removed from the pan immediately after cooling)-- using the ends of foil you folded over, lift the brownies out of the pan.
With a nice sized sharpened knife, cut into bars.
Remove the brownies from the foil and store in an airtight container at room temperature for four to five days.