Heat oven to 350ºF. Line the bottom of an 8x8 pan with lightly greased parchment paper.
In a mixing bowl, stir together the flour and corn starch. Mix in the sugar, cocoa powder, salt, and coffee (if using). Stir in the oil, water, corn syrup, eggs, and vanilla extract. Mix until combined into a very thick, glossy batter. Stir in the chocolate chips.
Spread batter into the prepared pan; sprinkle with vanilla salt. Bake 35-40 minutes, or until a toothpick inserted into the center comes out clean. Let cool; cut into 16 brownies.
To make vanilla salt, combine 2 tablespoons of coarse sea salt with 1 scraped vanilla bean. Store in an airtight container along with the bean pod.