Preheat the oven to 350 degrees Fahrenheit. 

In a large mixing bowl or bowl of a stand mixer, add the room temperature butter and sugar.

Beat together until well incorporated, about 30 seconds.

Beat in the egg and vanilla.

Beat in all remaining ingredients until a dough forms. It should look a bit like sugar cookie dough. 

Press into a 9x9 or 8x8 baking dish lined with parchment paper. You can use either size for this recipe, but an 8x8 will yield a thicker crust and bars. I used an 8x8 for reference, but it works in both!

Use your hands to spread evenly into the pan, then press down with a spatula to get rid of any fingerprints and even it out. 

Sprinkle on top the chopped pretzels and press gently into the crust.

Bake for 20 minutes or until the edges are slightly golden brown. 

While baking, add all ingredients for the caramel to a medium pot on the stove. Heat over medium heat and bring to a boil, whisking occasionally. Remove from heat and let cool to thicken. 

When the crust is done, stick in the fridge to let it cool slightly for about 5-10 minutes. You don't want the caramel or crust to be too hot when you combine. Slightly warm is fine, but not hot. 

While you're waiting, melt the coconut oil in a pot on the stove. Add in the chocolate chips and melt together, stirring occasionally so it doesn't burn. If you have a double boiler, use it here. 

Whisk in the chocolate baking mix and milk if needed. 

Once the crust and caramel are cool, pour the caramel on top of the crust and spread evenly with a rubber spatula. 

Pour the chocolate on top and carefully spread, trying not to combine the caramel and chocolate. Top with crushed pretzels and a sprinkle of sea salt. 

Place in the fridge for about 2 hours to set, or in the freezer for about 30-45 minutes. 

Once the chocolate is completely set, remove from the pan (the parchment paper should lift right out, but you can take a knife and slice the edges to make sure nothing is stuck) and slice into 16 even bars. To make sure it's set, press down with your finger or wiggle the pan. If the chocolate jiggles or leaves an indent, let it set for longer or the slicing can get messy!