Preheat oven to 325 degrees (F). Spray a 10″ oven safe skillet lightly with non-stick baking spray and set aside.
In a large bowl, sift together the flour, baking powder, salt, and cocoa powder. Set aside until needed.
In a large bowl, combine the butter, chopped chocolate, and oil. Melt in the microwave, on low heat, and in 30 second increments, stirring in between each increment, until the butter and chocolate are completely melted. Stir in the espresso powder and set aside.
In a large mixing bowl, combine the vanilla, eggs, yolk, and both sugars. Whisk until well combined, about 30 seconds.
Slowly, pour the warm butter mixture into the egg mixture, adding it very gradually (a little bit at a time) and whisking constantly until completely combined.
Add in the dry ingredients and chocolate chips and, using a rubber spatula, slowly stir until just combined. *Do not over mix! Stop staring when you see the last trace of dry ingredients. Over mixing will give you cakey brownies.
Scrape the batter into the prepared pan and smooth the top.
Bake for 26 minutes, or until the edges are firm and the top is shiny and slightly cracked.
Serve warm, with ice cream and plenty of spoons!
