Line an 8x8-inch square pan with parchment paper, leaving an overhang for easy removal.

Place 2 cups of the chocolate chips or chopped chocolate in a microwave-safe bowl. Microwave in 20–25 second bursts at 50% power, stirring between bursts, until about three-quarters melted and glossy. Stir until smooth.

Stir in the remaining 1/2 cup of chocolate chips to the melted chocolate to cool it slightly and improve sheen; stir until the added chips melt into the mixture.

Pour about two-thirds of the melted chocolate into the prepared pan and spread into an even layer with an offset spatula or the back of a spoon.

Arrange half of the toasted pecan halves over the chocolate layer and press them gently into the warm chocolate so they adhere.

Unwrap the Rolo candies and arrange half of them across the pan on top of the pecans and chocolate, pressing each Rolo gently so the caramel contacts the chocolate base.

Spoon the remaining melted chocolate over the top to cover the Rolos and pecans, smoothing the surface with an offset spatula. If the chocolate has thickened, warm it briefly for 8–10 seconds and stir before pouring.

Scatter the remaining pecan halves across the top and press them lightly into the chocolate so they set flush with the surface. Place the remaining Rolos on top as well, pressing gently so they are partly submerged in the top chocolate layer.

Let the pan sit at room temperature until the chocolate is almost set—about 30 minutes—then transfer to the refrigerator and chill for at least 1 hour, or until fully firm.

When fully set, lift the parchment overhang to remove the block from the pan. Place on a cutting board and slice into 16 squares using a sharp knife. For clean edges, warm the knife under hot water, dry it, then slice; wipe the knife between cuts.

Serve chilled or at cool room temperature. Store leftovers in an airtight container in the refrigerator for up to 2 weeks or freeze for longer storage.