Line a baking sheet with parchment paper to prepare for setting the clusters.
Chop the chocolate into small pieces to help it melt evenly, then place it in a heat-proof bowl.
Set a saucepan with a few inches of water over low heat to create a gentle simmer. Place the bowl of chocolate on top, ensuring it doesn’t touch the water.
Stir the chocolate constantly with a spatula as it melts, watching for a glossy, smooth texture with no lumps. This should take about 3-5 minutes.
Once melted, remove the bowl from heat and quickly stir in the butter until the mixture is shiny and smooth.
Add the roasted peanuts to the melted chocolate and gently fold them in with the spatula, coating each nut evenly in the glossy mixture.
Use a cookie scoop or two spoons to drop spoonfuls of the chocolate-peanut mixture onto the prepared parchment paper, spacing them about 2 inches apart.
Let the clusters set at room temperature for about 30 minutes, or place in the fridge for 15-20 minutes for quicker firming.
Check that the clusters are firm, shiny, and hold their shape, with the peanuts crunchy inside. Gently peel them off the parchment paper.
Store the clusters in an airtight container at room temperature for up to a week, or freeze for longer storage. Enjoy the rich chocolate and salty crunch in each bite!