Add vanilla, beating until well combined. Beat in cooled chocolate mixture until well combined. Whisk in dry ingredients until well combined. Fold in chocolate chips.
Mix together 3 tbsp tahini with 1 tbsp sugar. Scatter 5-6 scoops of sweetened tahini on top of brownie batter. Using a toothpick, create swirls of tahini through the brownie batter.
Bake at 350 F for 22-26 minutes. Cool in pan on a cooling rack for 30 minutes. Cool an additional 20-30 minutes on cooling rack. Top with flaky salt, slice and enjoy!