Line an 8×8 inch square baking pan with parchment paper, making sure the paper hangs over the edges for easy removal. In a medium bowl, combine the crushed pretzels, 1/2 cup of melted butter, and 1/4 cup of brown sugar. Stir until the mixture looks like wet sand, then press it firmly and evenly into the bottom of the prepared pan. Place the pan in the freezer for about 10 minutes to set while you prepare the next layer.
In a small saucepan over medium heat, melt 1 cup of butter and 1 cup of light brown sugar together. Bring the mixture to a gentle boil, stirring constantly. Once it begins to bubble, let it cook for exactly 3 minutes without stopping your stirring to ensure it does not burn. This step is crucial for getting the right consistency that holds its shape but remains soft enough to bite through easily.
Remove the saucepan from the heat and carefully stir in the heavy cream, alcohol-free vanilla extract, and sea salt. The mixture may bubble up vigorously, so be cautious. Continue stirring until the caramel is smooth and glossy. Take the pretzel base out of the freezer and pour the hot caramel evenly over the top. Smooth it out with a spatula and return the pan to the refrigerator for at least 45 minutes to 1 hour until the caramel is firm.
In a microwave-safe bowl, combine the chocolate chips and coconut oil. Heat in 30-second intervals, stirring well between each session, until the chocolate is completely melted and silky. The coconut oil helps the chocolate stay slightly soft after chilling, which prevents it from cracking when you slice the bars. Pour the chocolate over the set caramel layer and spread it to the edges.
While the chocolate is still wet, sprinkle a generous pinch of flaky sea salt across the top to enhance the flavors. Place the pan back into the refrigerator for at least another hour, or until the chocolate has completely hardened. For the best results, let the bars sit at room temperature for 5 to 10 minutes before slicing into squares with a sharp knife.
