Set your oven to 350 degrees. Then, line a small baking dish with parchment paper.
Sift the cornstarch and cocoa powder and set aside.
In a small sauce pan over medium heat, mix the three chocolates, oil, and 1 tablespoon of tahini. Mix until smooth.
Time for the mixer - beat the eggs and sugar for about 4 minutes.
Then, add in the molasses, salt and vanilla. Mix one minute.
Add in the chocolate mixture (make sure it's cooled a bit - you don't want to cook the eggs). Combine for about 1 minute.
Next, add in the dry ingredients and mix until blended.
Pour the batter into the small lined pan. It'll be thick, so be sure to get every last drop.
In a small dish mix the remaining tahini and agave together.
Dollop on top of the brownie and use a skewer to make some swirls. I went back and forth about 12 times to get these perfect swirls.
Bake about 23-27 minutes, take out of the oven and let them set for about 10. Then, place on a cutting board for an hour, then cut and eat.