First, make your caramel by bringing the coconut milk and coconut sugar to a boil over medium-high heat. Reduce heat to medium low and then, stirring occasionally, continue to simmer for about 30 minutes, or until mixture becomes thick and syrupy. Remove from heat and vigorously stir in vanilla and coconut oil. Transfer to glass jar or container and put in freezer for about an hour, or until mixture thickens.
Preheat oven to 350 degrees, then mix together all the wet ingredients for the brownies; set aside. Mix together all dry ingredients then add to wet, stirring until well incorporated. You may have to use your hands for this – it gets quite thick, more like a sugar cookie dough than traditional brownie dough. Press it fully into the bottom of a parchment-lined 8″ x 8″ pan, then remove caramel from freezer and spread a thick layer over the brownie batter, stopping about 1″ from each of the edges. Lift one half of the brownie batter and fold it in half, so you’re essentially sandwiching the caramel between the two brownie halves (like a Pop Tart). Press edges shut. The brownie will now take up only half the pan – this is okay, it’ll spread as it bakes.
Sprinkle the sea salt evenly over the top, then pop into the oven for 35 minutes. You can either drizzle the remaining caramel over top after removing from the oven, or do it as you serve, topping individual brownies. If you store brownies after drizzling the caramel, it hardens slightly into a lovely, gooey, caramel-ly topping. Makes about 12 brownies.