Preheat the oven to 325°F (163°C). Grease an 8x8-inch metal brownie pan with pan spray.
In a small bowl, whisk together the flour, baking powder, and salt. Set aside.
In a small saucepan over low heat, combine the olive oil, butter, white sugar, and brown sugar. Stir until the butter is fully melted and the sugars are incorporated.
Remove from heat and add the milk chocolate chips, stirring until melted.
Whisk the Dutch-processed cocoa powder (or substitute regular cocoa powder) into the warm chocolate mixture until smooth and lump-free.
Stir in the vanilla extract and eggs, whisking thoroughly until fully combined. Let the mixture rest for 10 minutes to allow the sugar to dissolve further.
Add the dry ingredient mixture to the wet ingredients and stir gently with a spatula until just combined.
Stir in the chopped dark chocolate chips until evenly distributed.
Pour the batter into the prepared 8x8-inch metal pan. Do not spread it with a spatula—this disrupts the brownie skin. Instead, firmly tap the pan on the counter multiple times to level out the batter.
Bake for 35 minutes, or until the middle has a temp. of 94-96C. Let the brownies cool in the pan for at least 60-90 minutes before cutting.
