An oldie but a goodie.
About 50 saltine crackers
16 tablespoons (2 sticks) unsalted butter
1 cup dark brown sugar
1 teaspoon vanilla extract
12 ounces semi-sweet chocolate pieces
1 cup finely chopped pecans
Flaky sea salt, such as Maldon
Preheat the oven to 400ºF. Line a 12-by-18-inch rimmed baking sheet with nonstick foil or parchment paper.
Lay the crackers out in one layer as close together as possible, filling the baking sheet.
Melt the butter, brown sugar, and vanilla in a medium saucepan over medium heat, stirring frequently. When the butter is melted, raise the heat and bring the mixture to a boil, and keep at a boil for about 3 minutes, stirring. When the 3 minutes are up, give it a good stir and pour evenly over the crackers on the baking sheet.
Spread the caramel around with a spatula if needed, but don’t worry if the surface isn’t covered completely, you just don’t want it pooling in one place. Bake the crackers for 5 minutes, then remove from the oven and immediately sprinkle the chocolate chips over the top in an even layer. Let sit for 5 minutes, then use a spatula to spread the chocolate in an even layer over the crackers.
Sprinkle the pecans and the sea salt evenly over the top of the toffee. Leave to cool, then place in the refrigerator for about an hour for the chocolate to set. Break into pieces and store in an airtight container.