Preheat your oven to 350°F (175°C). Line an 8-by-8-inch baking pan with aluminum foil and spray with cooking spray.

In a large microwave-safe bowl, melt the butter in the microwave for about 1 minute on high. Let it cool slightly, then whisk in the egg, brown sugar, and vanilla extract until smooth.

Stir in the flour and salt until just combined, being careful not to overmix. Fold in the chocolate chips.

Pour just over half of the batter (approximately 60%) into the prepared pan, spreading it out to cover the bottom in a thin layer.

Arrange the Rolos evenly on top of the batter, placing each candy upright on its base in 6 rows of 6.

Drop the remaining batter in heaping tablespoons over the Rolos, then use a spatula to gently smooth the batter blobs together.

Bake for 20 to 22 minutes, until the top is set but not overbaked.

Let cool in the pan on a wire rack for at least 90 minutes before slicing and serving.