- Preheat the oven to 350°F. Lightly spray two 4½-inch tart pans with cooking spray.
- To make the crust : Combine the pretzels, sugar, and oat flour in a food processor and process into a coarse flour. Transfer to a large bowl and cut in the butter until it’s a crumbly dough that holds together when squeezed.
- Divide the dough between the two tart pans and press into the bottom and up the sides. Bake for about 12 minutes, until dark golden brown. Cool completely in the pans on a cooling rack.
- To make the caramel : Combine the ingredients in a food processor. Process until smooth. Divide the mixture between the two crusts and refrigerate for 30 minutes.
- To make the ganache : Place the chocolate in a heatproof bowl. Bring the coconut milk to a boil over medium heat, then immediately remove from the heat and pour over the chocolate.
- Let it rest for a few minutes before gently stirring until smooth. Stir in the coconut oil. Pour the ganache over the tarts and spread it out evenly. Sprinkle the tops with flaked sea salt, if desired.
- Refrigerate the tarts until the chocolate is firm, at least 1 to 2 hours. Keep chilled until ready to serve. Leftovers will keep in airtight containers in the fridge for 2 to 3 days.