Preheat the oven to 325°F. Spray a 13x9-inch baking pan with nonstick spray.
PREPARE THE FILLING:
In a medium bowl, use an electric mixer to combine the cream cheese with the sugar until smooth. Add the egg and flour and beat well. Set aside.
PREPARE THE BROWNIES:
In a small bowl, whisk together the flour, baking powder and salt. Set aside.
In a medium saucepan, melt the butter with the chocolate over low heat, stirring occasionally, until smooth. Remove from heat, transfer to a large bowl, and allow to cool for about 5 minutes. Whisk in the sugar. Add the eggs, milk, and vanilla and whisk some more. Whisk in the dry ingredients. Stir in half of the pecans and half of the Heath Bars.
Reserve 1/2 cup of the brownie batter and set it aside. Spread the rest of the batter evenly in the prepared pan. Drop the cream cheese mixture by tablespoonfuls over the batter. Next, drop the reserved brownie batter by teaspoonfuls in between the cream cheese filling. Using a knife, swirl the two batters together, forming a decorative pattern.
Sprinkle the remaining pecans and Heath Bars over the top, and using a spatula, lightly press into the batter.
Bake 40 to 50 minutes, or until a toothpick inserted in the center comes out with moist crumbs attached. Do not over-bake. Allow to cool completely (preferably overnight) before cutting and serving.
Notes
How to toast the Pecans: Place the pecans on a baking sheet. Bake in a 350 degree F. oven for 5 to 7 minutes, or until lightly browned and fragrant. Keep an eye on them so they don't brown too quickly or burn.