To make the crust:

Preheat the oven to 350 degrees. Spray an 8x8x2 baking pan with cooking spray. Line with parchment so that the paper extends up and past at least two sides of the pan (a parchment sling, as it were) and set aside.

Place the saltines, cocoa powder, and sugar in the bowl of a food processor, and process the saltines until they are finely ground. Scrape the bowl with a rubber spatula and add the melted butter. Process until the butter is fully incorporated, scraping down the bowl as needed. Transfer the saltine mixture to the prepared pan, and using your hands, lightly press the crumbs into the bottom of the pan, making the crust into as even and solid a layer as possible.

Bake the crust for 8 minutes, rotating after 4. The crust should be fragrant when you remove it from the oven. Set it aside to cool.

To make the salty caramel:

Combine all of the ingredients in a medium sized sauce pan. Turn the heat to medium and stir the mixture constantly, until the sugar and butter melt. Turn the heat to medium-high, attach a candy thermometer to the side of the pan and allow the caramel to come to the soft-ball stage, 240 degrees (this took at least 15 minutes on my induction cooktop — be patient, but do not be tempted to turn up the heat). Do not stir the mixture while it cooks.

Once it reaches soft-ball, quickly remove the pan from the heat and carefully pour the caramel over the crust in the prepared pan and place it in the refrigerator to cool for at least three hours, or, preferably, overnight.

If not topping the bar with chocolate, remove the pan from the refrigerator once the caramel is quite firm and the pan is cool to the touch (if you slice your bars too early, your crust will be super crumbly). Holding on to the parchment paper, lift the caramel bars from the pan and place on a cutting board. Peel away the parchment and using a large chef's knife, cut the bars into tiny squares (I recommend making six slices along one side, and six slices along the other). Sprinkle with flaky sea salt and let sit for 30 minutes before serving.

Once you serve the bars, do not be concerned if they get a bit oozy as they sit on the serving platter. or place the bars in the fridge again to firm up. The bars will keep at least 3 to 5 days in the fridge tightly covered.

To make the chocolate topping:

If topping the bar with chocolate, place the chocolate and cream in a microwave safe bowl and heat the mixture on high in 30 second increments, stirring the mixture thoroughly after each one. Once the chocolate has melted, the cream is completely incorporated, and the mixture is glossy, pour it over caramel that has cooled for at least two hours, and use a small offset spatula to spread the chocolate evenly.

Place the pan back in the refrigerator until the chocolate has hardened, at least an hour. Remove the chocolate-covered bar from its pan, using the parchment paper to lift it out, and place it on a cutting board. Peel away the parchment paper and using a large chef's knife, cut the caramel into 36 tiny bars (I recommend making six slices on one side and six on the other). Sprinkle with flaky sea salt and let sit for 30 minutes before serving.

Once you serve the bars, do not be concerned if they get a bit oozy as they sit on the serving platter. But if the ooziness totally bums you out, place the bars in the fridge again to firm up. The bars will keep at least 3 to 5 days in the fridge tightly covered.