1. Preheat the oven to 350°F. Line an 8×8-inch baking pan with parchment paper, leaving overhang on the sides for easy removal.

2. In a large microwave-safe bowl, melt the butter and semi-sweet chocolate chips together in 20-second intervals, stirring after each, until smooth.

3. Whisk in 1 1/4 cups of the granulated sugar. Add 2 eggs and 1 teaspoon vanilla extract, then whisk until glossy.

4. Fold in the flour, cocoa powder, and salt just until no dry streaks remain.

5. In a separate bowl, beat the softened cream cheese with the remaining 1/2 cup granulated sugar until smooth.

6. Add the remaining 1 egg and 1 teaspoon vanilla extract to the cream cheese mixture and beat until creamy.

7. Fold the crushed chocolate sandwich cookies into the cream cheese mixture.

8. Spread about two-thirds of the brownie batter into the prepared pan.

9. Spoon the cream cheese mixture evenly over the brownie layer and gently spread it out.

10. Dollop the remaining brownie batter over the cream cheese layer and lightly swirl with a knife.

11. Top with the whole or halved chocolate sandwich cookies.

12. Bake for 35 to 42 minutes, until the edges are set and the center is only slightly jiggly.

13. Cool completely in the pan, then chill for 1 hour for cleaner slices.

14. Lift out, cut into squares, and serve.