Preheat the oven to 350 degrees F and line two baking sheets with parchment paper.
Place the nutella in a piping bag with a small round piping tip. Set aside.
In a small bowl, combine the flour, cocoa powder, baking powder, and salt. Set aside.
In a medium heat proof bowl add the chocolate and oil, and place over a small saucepan with simmering water. Stir occasionally until completely melted. Remove from heat and set aside.
In the bowl of a stand mixer fitted with the whisk attachment, whip the granulated sugar, brown sugar, eggs, and vanilla on high speed for 2-3 minutes until light and pale in color.
While mixing on low speed, drizzle in the melted chocolate mixture and mix until fully combined.
Lastly add in the dry ingredients and mix until just combined. The batter should soft, but able to hold a ball shape when scooped.
Immediately scoop the batter onto the prepared baking sheets about two inches apart. Inject each cookie dough ball with nutella.
Bake the cookies for about 8-10 minutes until they are crackly, shiny, and appear set. Allow to cool completely on baking sheet.