Peanut Butter Marbled Brownies

My mom gave me this recipe and she said it would make my roommates love me if I made it for them. So while I haven't tried it yet, it does sound yummy!

6 oz. cream cheese, softened
1/2 C. peanut butter
1/4 C. white sugar
1 egg
2 Tabl. milk
1 C. butter or margarine, melted
2 C. white sugar
2 tsp. vanilla extract
3 eggs
3/4 C. unsweetened cocoa powder
1 1/4 C. all-purpose flour
1/2 tsp. baking powder
1/4 tsp. salt
1 C. semisweet chocolate chips

Preheat oven to 350 degrees. Grease one 9x13 inch baking pan (glass works best.) In a medium bowl, beat cream cheese, peanut butter, 1/4 C. white sugar, 1 egg, and milk until smooth. Set aside.
In a large bowl, mix together melted butter, 2 C. white sugar, and vanilla. Mix in the remaining 3 eggs one at a time, beating well after each addition. Combine the flour, cocoa, baking powder, and salt; mix into the batter. Stir in chocolate chips. Remove 1 C. of the chocolate batter. Spread the remaining batter into the prepared pan. Spread the peanut butter filling over the top. Drop the reserved chocolate batter by teaspoonful over the filling. Using a knife, gently swirl thru the top layers for a marbled effect.
Bake in preheated oven for 35 to 40 minutes, or until a wooden toothpick inserted near the center comes out almost clean. Cool completely, then cut into bars.
Serve with milk or ice cream!