For the brownies: Preheat oven to 350°F/175°C. In a medium saucepan over low heat, melt the butter and chocolate chips. Stir constantly and remove from heat when the chocolate is fully melted. Whisk in the sugar and vanilla. Add eggs; whisk to incorporate after each one. Add the flour and salt and stir to combine. Pour the batter into a greased 9 X 13-inch pan. Bake for 20 minutes. Turn the heat down to 325 and bake for 10 more minutes. Remove from the oven and let the brownies cool completely.
For the Oreo truffle topping: Lightly crush the cookies and then mix with the softened cream cheese using an electric mixer until well-combined. Gently press the mixture over the cooled brownies.
In a small microwave-safe bowl, melt the chocolate or almond bark on low power at 30-second intervals, stirring in between, until melted and smooth. Pour the chocolate into the corner of a ziploc bag. Carefully snip a small piece off the corner and drizzle the chocolate across the brownies.
Chill the brownies in the refrigerator until the chocolate is set (10-20 minutes). Serve and enjoy!