How to Make It
In a food processor, pulse the chocolate until it is the size of peas. Transfer to a plate and freeze for 30 minutes.
Preheat the oven to 300°. Line a large rimmed baking sheet with parchment paper. In the bowl of a standing electric mixer fitted with the paddle, mix the matzo meal, granulated sugar, cocoa powder, and salt on low speed until well blended.
At low speed, gradually add the melted butter and mix until small clusters begin to form, about 30 seconds to 1 minute. Spread the crumbles on the prepared baking sheet in an even layer. Bake for 20 to 25 minutes, until slightly dried but still moist; stir the crumbles and rotate the pan halfway through baking. Let the crumbles stand at room temperature until cool and crisp. Transfer to an airtight container.
Ice cream and caramel sauce to make sundaes.