Line an 8x4-inch loaf pan with parchment paper, leaving an overhang on the sides for easy removal.

Place the raw walnuts in a food processor and pulse until they reach a fine, crumbly texture.

Add the 1.5 cups of pitted dates, cacao powder, 1 teaspoon of vanilla extract, and 1/4 teaspoon of sea salt to the processor. Process until the mixture is well-combined and forms a sticky dough that holds together when pressed.

Transfer the brownie dough to the prepared loaf pan. Use a spatula or the bottom of a measuring cup to press the mixture into a firm, even layer. Place the pan in the freezer.

To prepare the caramel, drain the soaked dates and place them in the food processor (no need to clean it). Add the almond butter, almond milk, 1/2 teaspoon of vanilla, and a pinch of salt. Process until completely smooth and creamy, scraping down the sides as necessary.

Remove the brownie base from the freezer and spread the date caramel evenly over the top.

Arrange the 16 pecan halves on top of the caramel layer in a 2x8 grid pattern.

Return the pan to the freezer for 30 minutes to allow the caramel to set.

Using the parchment overhang, lift the brownies out of the pan. Slice into 16 uniform squares.

Drizzle the melted vegan dark chocolate over each bite and serve immediately or store in an airtight container in the refrigerator.