Preheat the oven to 160° C - 325°F and place a rack in the middle of it.
Line a 20 x 20 cm - 8 × 8-inch (or similarly dimensioned) square pan with parchment paper cut into strips, crossing over each other, with plenty of overhang on both sides to help lift the brownie out after baking.
In a large bowl, combine 2/3 c olive oil, 2 eggs, 2 egg yolks, 1 t vanilla extract, 1 1/2 c powdered and 1/2 c dark brown sugars. Whisk together until smooth and glossy.
In a medium bowl, whisk together 3/4 all-purpose flour, 2/3 unsweetened cocoa powder, 1/2 t salt, 1/2 t MSG, and 1 t instant coffee.
Now gently whisk the flour mixture into the egg yolk mixture until well combined.
Using a spatula, fold in 6 oz - 170 g of coarsely chopped dark chocolate until evenly distributed before pouring the brownie batter into the parchment-lined pan.
Stud the surface of the batter with the chopped Snickers of Milky Ways cut into 1" - 2.5 cm pieces before baking.
Bake for 40 to 45 minutes, or until a toothpick inserted into the center comes up with only a few moist crumbs. Transfer the pan to a wire rack and allow to cool completely.
When it’s cooled, use the parchment overhang to lift the brownie out of the pan. Cut into 9 squares and serve.