Matzo toffee is an irresistible Passover dessert with sweet toffee and chocolate balanced by salty matzo with flaky sea salt. Easy to make and only five ingredients!
Preheat oven to 350°F (177°C) with a rack centered in the oven.
Prepare one rimmed baking sheet. Use a baker's half sheet which is about 13 x 18 inches. Line the sheet with aluminum foil making sure that the foil goes up the sides to catch any drips.
Arrange the matzo boards in a single even layer on the baking sheet. Break a couple matzos into thinner strips to fit and completely fill the whole sheet without overlapping. Set aside.
Make the caramel sauce in a 3 quart saucepan by melting the butter and sugar on the stovetop at medium heat stirring continuously with a silicone spatula or whisk. Make sure that the sugar has fully dissolved so that the sauce is not grainy. Once the caramel sauce comes to a boil, keep stirring, and let boil for about 2 minutes until the mixture is very bubbly and has thickened a little. Remove from heat.
Pour sauce immediately over the matzo, taking care as the sauce is very hot. Use an off-set spatula or rubber spatula to quickly spread the caramel covering the surface of each matzo. It doesn't have to be perfect because the sauce will continue to melt and spread in the oven.
Cook in oven. Next put the baking sheet in the oven for about 6 to 7 minutes. The caramel continues to cook and bubble. Remove from oven.
Add toppings. Immediately sprinkle mini chocolate chips and finishing salt over the toffee layer. Most of the chips should stick to the caramel once cooled. It's OK if some fall off.
Chill. Wait for the chips and caramel to harden: this takes about 30 minutes in the freezer, 1 hour in the refrigerator, or 2 hours at room temperature. The caramel is more likely to stay shiny looking if it dries at room temperature.
Break and Store. Once the candy is set, gently break or cut into irregularly shaped pieces. Store in an airtight container, and separate layers with wax paper or parchment. Keeps at room temperature for up to 1 week or can be frozen for up to 1 month. Leave on counter to come to room temperature before serving.