Preheat oven to 400°F. Line an 11" x 17" jellyroll pan with foil then grease the foil with butter.
Arrange the matzohs in a single layer covering the entire bottom of the jelly roll pan. (You will need to break some of the matzohs to make them fit. Break them into as few pieces as possible to create a single, even layer.)
Place the butter and brown sugar together in a small heavy saucepan over medium heat and cook, stirring often, until the butter melts completely.
Increase heat to high and bring the mixture to a boil. Boil undisturbed for 3 minutes.
Immediately pour the hot sugar mixture over the matzohs, spreading it if needed to cover the matzohs completely.
Bake for five minutes until the whole surface of the pan is bubbly.
Remove from the oven and immediately sprinkle with chocolate chips. Let stand for about five minutes to allow the chips to melt.
Use a small knife or spatula to spread the melted chips into an even coating of chocolate.
Sprinkle pecans over the top, pressing them gently to help them adhere.
Allow the toffee crunch to cool to room temperature then refrigerate until the entire pan is well chilled. Break into chunks.
Matzoh Toffee Crunch can be stored in an airtight container at room temperature for up to 5 days, or frozen for up to 1 month.