1-1/2 cups semi-sweet chocolate chips for frosting (optional)
Preheat oven to 350 degrees F. Line a 9-inch by 13-inch baking pan with non-stick foil. Combine brownie mix, 2 eggs, vegetable oil, and water in a large bowl. Stir with a fork only until combined. Pour into prepared pan and smooth evenly.
Beat cream cheese, 1 egg, and confectioners' sugar until smooth. Mix in raspberry extract. Plop dollops of creamcheese mixture over the top of the brownie mix. Using a dull butter knife, swirl the cheesecake mixture into the brownies.
Bake 30 minutes. If frosting, sprinkle chocolate chips evenly over the top of the hot brownies immediately after removing from the oven. Tent with foil and wait about 5 minutes for chocolatechips to soften. Use a spatula to gently smooth the melted chips evenly over the brownies. Let cool to room temperature before lifting out of the pan and cutting.