Line or spray an 8x8 pan. Set aside. Preheat the oven to 350℉.
In a microwave safe bowl, add the chocolate, butter and oil. Heat in the microwave in 30 second increments until fully melted, stirring in between each time. Stir in the vanilla extract.
While the chocolate mixture warms, add the eggs and sugar to the bowl of a stand mixer or large mixing bowl. Using the whisk attachment, whisk at medium-high speed for about 3 minutes until the batter is pale and ribbony.
Gently whisk in the chocolate mixture until fully incorporated. Then add in the flour, cocoa powder, espresso if using and salt. Using a spatula, gently fold together until almost combined.
Pour the batter into your lined pan and sprinkle the 1 tbsp sprinkles on top. Bake for 23-25 minutes or until a toothpick inserted about 2/3 of the way to the centre comes out with moist crumbs. Do not overbake!
Let fully cool before slicing and serving. Store in an airtight container for up to 3 days and enjoy!
While the brownies cool, make your frosting by adding the butter, cocoa, 1 1/2 tbsp milk and vanilla into a medium sized bowl. Using a hand or stand mixer, beat at medium speed for 1 minute. Then add in the icing sugar and beat for an additional minute. If frosting is too thick, add another 1/2 tbsp of milk to thin it out.
Once the brownies are fully cooled, spread your frosting on top and sprinkle the remaining 2 tbsp sprinkles on top and enjoy!